Terminal file viewer/editor + per-window app-command lockdown (#60)

Clicking a file path in Claude's terminal output now opens the file in its own window with a CodeMirror 6 editor. The editor highlights the target line, live-reloads while the file changes, and saves explicitly with hash-based conflict detection. The viewer commands are gated by window label.

Every app command is now ACL-gated per window through a Tauri AppManifest. build.rs checks the handler list against the capability files and fails the build on any mismatch.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

.gitea/workflows/build-app-preview.yml

@@ -43,7 +43,18 @@ name: Build App (Preview)
 # prunes previous previews itself, keeping the newest few. Bundles are ~130 MB a
 # release; the point of a preview is the build you are testing now.
 #
-# `sync-release.yml` is workflow_dispatch-only, so nothing here reaches GitHub.
+# A preview release is not meant to reach GitHub. `build-app.yml`'s inline
+# mirror never sees one (it only runs for its own `push`-triggered release),
+# but `backfill-releases.yml` pulls every Gitea release unfiltered and would
+# faithfully forward a preview's `prerelease: true` if it were ever dispatched
+# while one existed — so `GitHubRelease::prerelease` in `update_commands.rs`
+# is real defence, not a no-op, even though the `preview-<sha>` tag shape
+# (never valid semver) already blocks it independently. (The previous
+# mechanism here, `sync-release.yml`, was `workflow_dispatch`-only and read
+# `gitea.event.release.*` fields that are only ever populated by a `release`
+# trigger, so it could never have actually run; deleted rather than fixed,
+# since build-app.yml's inline mirror already does what it was meant to do
+# for real releases. See triple-c#32.)
 
 env:
   GITEA_URL: ${{ gitea.server_url }}
@@ -70,12 +81,23 @@ jobs:
     outputs:
       version: ${{ steps.version.outputs.VERSION }}
       sha: ${{ steps.version.outputs.SHA }}
+      # Everything after the first `-` in VERSION (e.g. `preview.a1b2c3d`).
+      # The bundle version fields never see this — see "Set app version" in
+      # each build job — but it is baked into the binary as
+      # `TRIPLE_C_BUILD_SUFFIX` so `get_app_version()` can still report it.
+      # An installed preview otherwise reports the same bare number a
+      # production build would, indistinguishable in the About panel and to
+      # `check_for_updates`. See triple-c#32.
+      suffix: ${{ steps.version.outputs.SUFFIX }}
     steps:
       - name: Checkout
         uses: actions/checkout@v4
         with:
           fetch-depth: 0
 
+      - name: Fetch all tags
+        run: git fetch --tags
+
       - name: Compute preview version
         id: version
         run: |
@@ -86,21 +108,60 @@ jobs:
           # is testing and not something to hang a tag on.
           echo "SHA=$(git rev-parse HEAD)" >> $GITHUB_OUTPUT
 
-          # The patch number is computed exactly as build-app.yml does it, so a
-          # preview is labelled with the version the release it previews would
-          # carry. This used to be hard-coded `.0`, which made every preview
-          # installer claim to be x.y.0 no matter what it contained.
-          LATEST_TAG=$(git tag -l "v${MAJOR_MINOR}.*" --sort=-v:refname | grep -E "^v${MAJOR_MINOR}\.[0-9]+$" | head -1 || true)
-          if [ -n "$LATEST_TAG" ]; then
-            PATCH=$(git rev-list --count "${LATEST_TAG}..HEAD")
-            echo "Latest matching tag: ${LATEST_TAG} (+${PATCH} commits)"
+          # The patch number must be the same "one past the highest patch
+          # already used" build-app.yml computes for a real release — not a
+          # distance from the latest tag. It used to be
+          # `git rev-list --count <latest tag>..HEAD`, which build-app.yml's
+          # own history section documents as broken for exactly this reason:
+          # it resets to zero on every tag cut, so previews went *backwards*
+          # (0.4.62 -> 0.4.0) the moment a release landed, and nothing stopped
+          # a preview number from later colliding with a real release's.
+          #
+          # Reading the same `v${MAJOR_MINOR}.*` tags (including the `-mac`
+          # / `-win` suffixed ones a partially-published release can leave
+          # behind) means a preview built right before a release computes the
+          # exact number that release is about to take — e.g. `0.4.13` for
+          # both. That makes the two numerically *equal*, not "preview less
+          # than release" — plain semver ordering does not make a
+          # `-preview.<sha>` suffix sort lower on its own here, because
+          # `check_for_updates` compares against the bare, stripped
+          # `CARGO_PKG_VERSION`, never the suffixed display string. What
+          # closes the loop is `update_commands.rs`'s `is_preview_build`
+          # check, which relaxes that one comparison to `>=` specifically so
+          # "a release exists at my own number" reads as an update. See
+          # triple-c#32.
+          HIGHEST=$(git tag -l "v${MAJOR_MINOR}.*" \
+            | grep -E "^v${MAJOR_MINOR}\.[0-9]+(-mac|-win)?$" \
+            | sed -E "s/^v${MAJOR_MINOR}\.([0-9]+).*/\1/" \
+            | sort -n | tail -1 || true)
+
+          # Mirrors build-app.yml's own `EXISTING` guard: this workflow is
+          # also `workflow_dispatch`-able on `main`, not just PR-triggered, so
+          # HEAD can be a commit a release was already cut from. Without this,
+          # dispatching a preview there would compute `HIGHEST + 1` — one past
+          # that release — and produce exactly the "preview outranks
+          # production" failure triple-c#32 was filed over, just reintroduced
+          # through the manual-dispatch door instead of the automatic one.
+          EXISTING=$(git tag --points-at HEAD \
+            | grep -E "^v${MAJOR_MINOR}\.[0-9]+$" \
+            | sed -E "s/^v${MAJOR_MINOR}\.([0-9]+)$/\1/" \
+            | sort -n | tail -1 || true)
+
+          if [ -n "$EXISTING" ]; then
+            echo "HEAD is already tagged v${MAJOR_MINOR}.${EXISTING} — matching it"
+            PATCH="${EXISTING}"
+          elif [ -n "$HIGHEST" ]; then
+            echo "Highest patch already used on this line: ${HIGHEST}"
+            PATCH=$((HIGHEST + 1))
           else
             echo "No v${MAJOR_MINOR}.* tag yet — starting this line at .0"
             PATCH=0
           fi
 
-          VERSION="${MAJOR_MINOR}.${PATCH}-preview.${SHORT_SHA}"
+          SUFFIX="preview.${SHORT_SHA}"
+          VERSION="${MAJOR_MINOR}.${PATCH}-${SUFFIX}"
           echo "VERSION=${VERSION}" >> $GITHUB_OUTPUT
+          echo "SUFFIX=${SUFFIX}" >> $GITHUB_OUTPUT
           echo "Computed preview version: ${VERSION}"
 
   # One release, created once. The three build jobs run concurrently, so
@@ -238,8 +299,34 @@ jobs:
       - name: Install frontend dependencies
         working-directory: ./app
         run: |
-          rm -rf node_modules package-lock.json
-          npm install
+          # `npm ci` — from the lockfile, never resolving afresh.
+          #
+          # This used to be `rm -rf node_modules package-lock.json && npm
+          # install`, which deleted the lockfile "to ensure correct
+          # platform-specific bindings" (2d4fce9). That made every build
+          # re-resolve the whole tree against the registry, so a dependency
+          # publishing a new version could break CI with no change to this
+          # repo — and one did. Deleting the lockfile then hit a null
+          # dereference in npm 10.9.8's arborist peer-set resolver:
+          #
+          #   npm error Cannot read properties of null (reading 'edgesOut')
+          #     at #loadPeerSet (.../build-ideal-tree.js:1289:38)
+          #
+          # reached through vite → @vitejs/devtools → @vitejs/devtools-vitest
+          # → vitest@* → @vitest/browser-playwright → jsdom@* → canvas.
+          # Reproduced exactly by removing the lockfile locally on the same
+          # Node 22.23.2 the runner installs.
+          #
+          # The binding worry is obsolete: the committed lockfile records 25
+          # rollup platform variants, and `npm ci` on Linux installs precisely
+          # rollup-linux-x64-{gnu,musl} and @esbuild/linux-x64. Verified, along
+          # with a clean tsc, a successful build and 752 passing tests from the
+          # resulting tree.
+          #
+          # Do not "fix" a future dependency error by deleting the lockfile
+          # again. If `npm ci` refuses, package.json and the lockfile have
+          # genuinely diverged, and the fix is to commit an updated lockfile.
+          npm ci
 
       - name: Install Tauri CLI
         working-directory: ./app
@@ -249,16 +336,31 @@ jobs:
 
       - name: Build Tauri app
         working-directory: ./app
+        env:
+          # Baked into the binary via `option_env!` in `get_app_version()` —
+          # the bundle version above stays bare (WiX/MSI's ProductVersion has
+          # no room for a suffix), so this is the only place a preview build
+          # can still tell itself apart from a production one. See
+          # triple-c#32.
+          TRIPLE_C_BUILD_SUFFIX: ${{ needs.compute-version.outputs.suffix }}
         run: |
           export PATH="$HOME/.cargo/bin:$PATH"
-          npx tauri build
+          # AppImage only: the .deb and .rpm were dropped in favour of the one
+          # artifact that runs everywhere, and building them is pure cost.
+          # Left as "all" in tauri.conf.json so macOS and Windows are unaffected.
+          npx tauri build --bundles appimage
+
+      # linuxdeploy bundles a libwayland-client.so.0 that shadows the host's
+      # and breaks Mesa's EGL on systems newer than the build runner, so the
+      # window comes up blank. It has to come from the host; see the script
+      # header for the evidence and the trade.
+      - name: Finalize the AppImage
+        run: bash scripts/finalize-appimage.sh app/src-tauri/target/release/bundle/appimage
 
       - name: Collect artifacts
         run: |
           mkdir -p artifacts
           cp app/src-tauri/target/release/bundle/appimage/*.AppImage artifacts/ 2>/dev/null || true
-          cp app/src-tauri/target/release/bundle/deb/*.deb artifacts/ 2>/dev/null || true
-          cp app/src-tauri/target/release/bundle/rpm/*.rpm artifacts/ 2>/dev/null || true
           ls -la artifacts/
 
       # Assets, not workflow artifacts — see the note at the top of this file.
@@ -350,8 +452,10 @@ jobs:
       - name: Install frontend dependencies
         working-directory: ./app
         run: |
-          rm -rf node_modules
-          npm install
+          # `npm ci` here too, so all three platforms install identically and
+          # none of them can re-resolve the tree mid-release. Windows already
+          # did. See the Linux job for what a fresh resolution cost us.
+          npm ci
 
       - name: Install Tauri CLI
         working-directory: ./app
@@ -361,6 +465,9 @@ jobs:
 
       - name: Build Tauri app (universal)
         working-directory: ./app
+        env:
+          # See the matching comment on the Linux job's "Build Tauri app" step.
+          TRIPLE_C_BUILD_SUFFIX: ${{ needs.compute-version.outputs.suffix }}
         run: |
           export PATH="$HOME/.cargo/bin:$PATH"
           npx tauri build --target universal-apple-darwin
@@ -489,6 +596,8 @@ jobs:
         working-directory: ./app
         env:
           TAURI_CONFIG: "{\"build\":{\"beforeBuildCommand\":\"\"}}"
+          # See the matching comment on the Linux job's "Build Tauri app" step.
+          TRIPLE_C_BUILD_SUFFIX: ${{ needs.compute-version.outputs.suffix }}
         run: |
           set "PATH=%USERPROFILE%\.cargo\bin;C:\Program Files\nodejs;%PATH%"
           cargo tauri build

.gitea/workflows/build-app.yml

@@ -172,8 +172,34 @@ jobs:
       - name: Install frontend dependencies
         working-directory: ./app
         run: |
-          rm -rf node_modules package-lock.json
-          npm install
+          # `npm ci` — from the lockfile, never resolving afresh.
+          #
+          # This used to be `rm -rf node_modules package-lock.json && npm
+          # install`, which deleted the lockfile "to ensure correct
+          # platform-specific bindings" (2d4fce9). That made every build
+          # re-resolve the whole tree against the registry, so a dependency
+          # publishing a new version could break CI with no change to this
+          # repo — and one did. Deleting the lockfile then hit a null
+          # dereference in npm 10.9.8's arborist peer-set resolver:
+          #
+          #   npm error Cannot read properties of null (reading 'edgesOut')
+          #     at #loadPeerSet (.../build-ideal-tree.js:1289:38)
+          #
+          # reached through vite → @vitejs/devtools → @vitejs/devtools-vitest
+          # → vitest@* → @vitest/browser-playwright → jsdom@* → canvas.
+          # Reproduced exactly by removing the lockfile locally on the same
+          # Node 22.23.2 the runner installs.
+          #
+          # The binding worry is obsolete: the committed lockfile records 25
+          # rollup platform variants, and `npm ci` on Linux installs precisely
+          # rollup-linux-x64-{gnu,musl} and @esbuild/linux-x64. Verified, along
+          # with a clean tsc, a successful build and 752 passing tests from the
+          # resulting tree.
+          #
+          # Do not "fix" a future dependency error by deleting the lockfile
+          # again. If `npm ci` refuses, package.json and the lockfile have
+          # genuinely diverged, and the fix is to commit an updated lockfile.
+          npm ci
 
       - name: Install Tauri CLI
         working-directory: ./app
@@ -185,16 +211,38 @@ jobs:
         working-directory: ./app
         run: |
           export PATH="$HOME/.cargo/bin:$PATH"
-          npx tauri build
+          # AppImage only: the .deb and .rpm were dropped in favour of the one
+          # artifact that runs everywhere, and building them is pure cost.
+          # Left as "all" in tauri.conf.json so macOS and Windows are unaffected.
+          npx tauri build --bundles appimage
+
+      # linuxdeploy bundles a libwayland-client.so.0 that shadows the host's
+      # and breaks Mesa's EGL on systems newer than the build runner, so the
+      # window comes up blank. It has to come from the host; see the script
+      # header for the evidence and the trade.
+      - name: Finalize the AppImage
+        run: bash scripts/finalize-appimage.sh app/src-tauri/target/release/bundle/appimage
 
       - name: Collect artifacts
         run: |
           mkdir -p artifacts
+          # The versioned AppImage only. The update channel's copy lives in
+          # bundle/appimage/update-channel/ precisely so this glob cannot pick
+          # it up and publish an 80 MB duplicate under a second name.
           cp app/src-tauri/target/release/bundle/appimage/*.AppImage artifacts/ 2>/dev/null || true
-          cp app/src-tauri/target/release/bundle/deb/*.deb artifacts/ 2>/dev/null || true
-          cp app/src-tauri/target/release/bundle/rpm/*.rpm artifacts/ 2>/dev/null || true
           ls -la artifacts/
 
+          # A green job that published nothing is the worst outcome available:
+          # the release exists, carries no AppImage, and nobody is told. The
+          # `|| true` above is there so a missing bundle does not mask the real
+          # error, which makes this check the thing that catches it.
+          shopt -s nullglob
+          collected=(artifacts/*)
+          if [ ${#collected[@]} -eq 0 ]; then
+            echo "No artifacts collected — the bundler produced nothing." >&2
+            exit 1
+          fi
+
       - name: Upload to Gitea release
         if: gitea.event_name == 'push'
         env:
@@ -270,6 +318,19 @@ jobs:
               "${GITEA_URL}/api/v1/repos/${REPO}/releases/${RELEASE_ID}/assets?name=${filename}"
           done
 
+      # The fixed tag every installed AppImage checks for updates. Separate
+      # from the versioned release above because the updater's URL must never
+      # move, and `releases/latest` does.
+      - name: Publish the Linux update channel
+        if: gitea.event_name == 'push'
+        env:
+          GH_PAT: ${{ secrets.GH_PAT }}
+          GITEA_TOKEN: ${{ secrets.REGISTRY_TOKEN }}
+          GITEA_SHA: ${{ gitea.sha }}
+        run: |
+          bash scripts/publish-update-channel.sh \
+            app/src-tauri/target/release/bundle/appimage/update-channel
+
   build-macos:
     runs-on: macos-latest
     needs: [compute-version]
@@ -325,8 +386,10 @@ jobs:
       - name: Install frontend dependencies
         working-directory: ./app
         run: |
-          rm -rf node_modules
-          npm install
+          # `npm ci` here too, so all three platforms install identically and
+          # none of them can re-resolve the tree mid-release. Windows already
+          # did. See the Linux job for what a fresh resolution cost us.
+          npm ci
 
       - name: Install Tauri CLI
         working-directory: ./app

.gitea/workflows/build.yml

@@ -28,6 +28,27 @@ jobs:
 
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
+        with:
+          # Put BuildKit in the host's network namespace so it can reach
+          # act_runner's cache service.
+          #
+          # The `docker-container` driver — which the multi-arch build below
+          # requires, since the plain `docker` driver cannot do
+          # linux/amd64+linux/arm64 — runs BuildKit in its *own* container on
+          # Docker's default bridge. act_runner advertises ACTIONS_CACHE_URL as
+          # an address the *job* container can reach, and nothing teaches the
+          # BuildKit container about it: the job could reach
+          # 192.168.1.126:40649 while the container actually making the request
+          # could not, and the build died with `no route to host`.
+          #
+          # `no route to host` is EHOSTUNREACH — a firewall rejecting, not a
+          # missing route (a wrong address times out instead) — which is what a
+          # default firewalld zone does to traffic arriving from the docker
+          # bridge. Sharing the host's namespace sidesteps the question
+          # entirely: the cache address becomes local to BuildKit.
+          #
+          # No effect on runners where this already worked.
+          driver-opts: network=host
 
       - name: Login to Gitea Container Registry
         uses: docker/login-action@v3
@@ -55,5 +76,21 @@ jobs:
             ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ gitea.sha }}
             ghcr.io/shadowdao/triple-c-sandbox:latest
             ghcr.io/shadowdao/triple-c-sandbox:${{ gitea.sha }}
+          # `ignore-error` is what stops a cache failure failing a build that
+          # already succeeded. act_runner emulates the GitHub Actions cache
+          # service on the runner host's LAN address, and the `docker-container`
+          # builder `setup-buildx-action` creates could not route to it —
+          # every layer of both arches built, then the job died on
+          # `GetCacheEntryDownloadURL: no route to host` while exporting.
+          #
+          # On a pull_request `push:` above is false, so this job pushes
+          # nothing and the cache is its only output: failing it discarded a
+          # complete, successful validation of the Dockerfile for both
+          # architectures. A cache is an optimisation and must degrade to
+          # "slow", never to "red".
+          #
+          # The import is already non-fatal — the build ran all 37 layers after
+          # warning that it could not read the cache — so only the exporter
+          # needs the flag.
           cache-from: type=gha
-          cache-to: type=gha,mode=max
+          cache-to: type=gha,mode=max,ignore-error=true

.gitea/workflows/secret-scan.yml

@@ -0,0 +1,32 @@
+name: Secret Scan
+
+# **No `paths:` filter, deliberately.** The credential this exists for lived in
+# `app/src-tauri/src/docker/container.rs`, which `build.yml` would have skipped —
+# that workflow only runs for `container/**`. A scan that can be avoided by
+# touching the wrong directory is not a scan.
+#
+# This is the half of the check that nobody can bypass. The pre-commit hook in
+# `.githooks/` is faster and friendlier, but it is opt-in per clone and
+# `--no-verify` skips it; both are true of every git hook and neither is fixable
+# from inside a repository.
+
+on:
+  push:
+    branches: ["**"]
+  pull_request:
+    branches: ["**"]
+
+jobs:
+  scan:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      # The whole tracked tree, not just the diff. Scanning a range is cheaper
+      # but depends on getting the range right across pushes, force-pushes,
+      # merges and PR events — and a wrong range fails *open*. The full scan
+      # takes under half a second on this repository and cannot be evaded by
+      # arranging for the interesting commit to sit outside the window.
+      - name: Scan tracked files for credentials
+        run: sh scripts/scan-secrets.sh --tracked

.gitea/workflows/sync-release.yml

@@ -1,59 +0,0 @@
-name: Sync Release to GitHub
-
-on:
-  workflow_dispatch:
-
-jobs:
-  sync-release:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Mirror release to GitHub
-        env:
-          GH_PAT: ${{ secrets.GH_PAT }}
-          GITHUB_REPO: shadowdao/triple-c
-          RELEASE_TAG: ${{ gitea.event.release.tag_name }}
-          RELEASE_NAME: ${{ gitea.event.release.name }}
-          RELEASE_BODY: ${{ gitea.event.release.body }}
-          IS_PRERELEASE: ${{ gitea.event.release.prerelease }}
-          IS_DRAFT: ${{ gitea.event.release.draft }}
-        run: |
-          set -e
-
-          echo "==> Creating release $RELEASE_TAG on GitHub..."
-
-          RESPONSE=$(curl -sf -X POST \
-            -H "Authorization: Bearer $GH_PAT" \
-            -H "Accept: application/vnd.github+json" \
-            -H "Content-Type: application/json" \
-            https://api.github.com/repos/$GITHUB_REPO/releases \
-            -d "{
-              \"tag_name\": \"$RELEASE_TAG\",
-              \"name\": \"$RELEASE_NAME\",
-              \"body\": $(echo "$RELEASE_BODY" | jq -Rs .),
-              \"draft\": $IS_DRAFT,
-              \"prerelease\": $IS_PRERELEASE
-            }")
-
-          UPLOAD_URL=$(echo "$RESPONSE" | jq -r '.upload_url' | sed 's/{?name,label}//')
-          echo "Release created. Upload URL: $UPLOAD_URL"
-
-          echo '${{ toJSON(gitea.event.release.assets) }}' | jq -c '.[]' | while read asset; do
-            ASSET_NAME=$(echo "$asset" | jq -r '.name')
-            ASSET_URL=$(echo "$asset" | jq -r '.browser_download_url')
-
-            echo "==> Downloading asset: $ASSET_NAME"
-            curl -sfL -o "/tmp/$ASSET_NAME" "$ASSET_URL"
-
-            echo "==> Uploading $ASSET_NAME to GitHub..."
-            ENCODED_NAME=$(python3 -c "import urllib.parse, sys; print(urllib.parse.quote(sys.argv[1]))" "$ASSET_NAME")
-            curl -sf -X POST \
-              -H "Authorization: Bearer $GH_PAT" \
-              -H "Accept: application/vnd.github+json" \
-              -H "Content-Type: application/octet-stream" \
-              --data-binary "@/tmp/$ASSET_NAME" \
-              "$UPLOAD_URL?name=$ENCODED_NAME"
-
-            echo "  Uploaded: $ASSET_NAME"
-          done
-
-          echo "==> Release sync complete."

.githooks/pre-commit

@@ -0,0 +1,14 @@
+#!/bin/sh
+# Refuse a commit that adds something shaped like a live credential.
+#
+# Installed by pointing git at this directory:
+#
+#     git config core.hooksPath .githooks
+#
+# which `npm run hooks` in app/ does for you. It is per-clone — git will not let
+# a repository configure its own hooks path, for the obvious reason that cloning
+# a repo would then be enough to run its code. So this is opt-in on every
+# machine, `--no-verify` skips it, and neither of those is a flaw to fix here:
+# the CI job in `.gitea/workflows/build.yml` is the half nobody can bypass. The
+# hook exists to tell you in one second rather than in five minutes.
+exec "$(git rev-parse --show-toplevel)/scripts/scan-secrets.sh" --staged

.gitignore

@@ -1,6 +1,9 @@
 node_modules/
 app/dist/
 app/src-tauri/target/
+# Written by build.rs (tauri-build AppManifest); gen/schemas/acl-manifests.json is the
+# tracked, reviewable form of the same information.
+app/src-tauri/permissions/autogenerated/
 Screenshot*.png
 code-review.md
 

BUILDING.md

@@ -71,13 +71,29 @@ npm ci
 npx tauri build
 ```
 
+Linux ships as **AppImage only**. To match what CI produces, pass the bundle
+explicitly:
+
+```bash
+npx tauri build --bundles appimage
+```
+
+The `.deb` and `.rpm` bundles were dropped — two more artifacts to build and
+publish for an audience the AppImage already serves, and neither could
+self-update. A bare `npx tauri build` still emits them, because
+`tauri.conf.json` keeps `"targets": "all"` so that macOS and Windows are
+untouched; they are not released and not tested.
+
 Build artifacts are located in `app/src-tauri/target/release/bundle/`:
 
-| Format     | Path                          |
-|------------|-------------------------------|
-| AppImage   | `appimage/*.AppImage`         |
-| Debian pkg | `deb/*.deb`                   |
-| RPM pkg    | `rpm/*.rpm`                   |
+| Format     | Path                          | Released |
+|------------|-------------------------------|----------|
+| AppImage   | `appimage/*.AppImage`         | yes      |
+| Debian pkg | `deb/*.deb`                   | no       |
+| RPM pkg    | `rpm/*.rpm`                   | no       |
+
+`scripts/finalize-appimage.sh` post-processes the AppImage; see the Packaging
+section of `CLAUDE.md` for why both of its steps are load-bearing.
 
 ## macOS
 

CLAUDE.md

@@ -73,20 +73,65 @@ docker exec stdout → tokio task → emit("terminal-output-{sessionId}") → li
 - **`hooks/`** — All Tauri IPC calls are encapsulated in hooks (`useTerminal`, `useProjects`, `useDocker`, `useSettings`)
 - **`lib/tauri-commands.ts`** — Typed `invoke()` wrappers; TypeScript types in `lib/types.ts` must match Rust models
 - **`components/terminal/TerminalView.tsx`** — xterm.js integration with WebGL rendering, URL detection for OAuth flow
+- **`viewer/`** — the terminal file viewer's window (second Vite entry `viewer.html` →
+  `src/viewer/main.tsx`; CodeMirror 6). `lib/filePathLinks.ts` decides what a path is;
+  `components/terminal/filePathLinkProvider.ts` registers it with xterm. The OSC 8 handler now
+  runs with `allowNonHttpProtocols` on and dispatches `file:` to the viewer, so every other scheme
+  must be refused *there*. `viewer.html` must never carry an inline `<style>` — Tauri would add a
+  style nonce and CodeMirror's injected styles would stop applying. A missing or broken
+  `viewer.html` Vite entry is not caught by Tauri at build time — both Vite dev and Tauri's asset
+  lookup silently fall back to `index.html`, so the window just opens the *main app*, full UI and
+  all, with no error anywhere; `file_viewer::tests::the_viewer_entry_exists_and_is_a_vite_input`
+  in `file_viewer/mod.rs` is the only thing pinning this.
 - **`components/layout/`** — TopBar, MainTabs (the unified tab strip), Sidebar, StatusBar
 - **`components/projects/`** — `ProjectRow` (select-only list row), `ProjectList`, `AddProjectDialog`,
   and the editors reused by Project Home
 - **`components/projects/home/`** — **Project Home**, the main-area view for a project:
   Overview / Sessions / Automation / Config / Files. Per-project configuration lives here, not in
   modals — see "UI conventions" below.
-  - **Files takes drops *in*, and that path does not use HTML5 drag.** Dropping into the pane
-    is Tauri's native `onDragDropEvent`, which is window-wide and therefore routed by a
-    hit-test of the physical-pixel payload position against the pane's rect ÷
-    `devicePixelRatio` — a hidden pane has a zero-size rect, which is what stops it and
-    `TerminalView`'s listener both firing. Keep `lib/dropTarget.ts` and both listeners.
-  - **Getting a file *out* is "Save to host…", and there is no other route.** OS drag-out —
-    `tauri-plugin-drag`, `stage_container_file_for_drag` and its host staging directory — was
-    removed from the ship branch and held back for separate hardening; it lives on
+  - **The Files pane's host transfers open their dialog from Rust, and that is the whole
+    design — do not move it back into the webview.** The tab browses, views (text and image),
+    renames and creates folders inside the container (`list_container_files`,
+    `read_container_file`, `rename_container_path`, `create_container_directory`), and it
+    copies single files in and out (`upload_files_to_container`, `download_container_file`).
+    The second pair call `pick_files_to_upload` / `pick_save_path`, which drive
+    `tauri-plugin-dialog` from the *backend*: the webview can ask for a picker and that is the
+    entirety of its influence — it cannot name a host path as an *input*. The claim stops
+    there and should not be widened: host paths still travel outward in error text, canonical
+    ones included. What is closed is the direction that produced the criticals.
+    That shape is not decoration. Four successive audits found that host filesystem paths
+    crossing IPC were where the criticals lived — a caller-named host destination for
+    container-controlled bytes, an arbitrary host source read into the container, a `link(2)`
+    upload reservation that succeeded against a directory and failed forever on any filesystem
+    without hard links. The feature was removed rather than fixed a fifth time, and it came
+    back only in the shape that removes the class: a frontend-driven dialog handing Rust a
+    string is the exact thing that failed, so re-introducing `open()`/`save()` in `FilesTab`
+    would undo the whole point while looking like a simplification.
+    None of the reservation machinery came back with it. There is no destination reservation,
+    no placeholder rollback and no collision marker — the OS save dialog already asks about
+    overwriting, and Docker's archive extractor overwrites on upload the way `cp` does.
+  - **Drag-and-drop is still not it.** There is no drop-into-the-Files-pane and no OS
+    drag-out; the buttons are the gesture. A file also gets *in* by being dropped on the
+    Terminal, and a whole tree comes *out* through "Back up container" — those two predate the
+    Files work and their hardening is not to be weakened. `TerminalView`'s `onDragDropEvent`
+    is Tauri's native drop event (window-wide, so routed by `lib/dropTarget.ts` — geometry for
+    *whose* drop it is, a document-wide `dropIsBlocked` for whether the app should accept one
+    at all; keep both halves and keep `PaneVisibility`). Backup is
+    `file_commands::download_container_backup`.
+  - **`resolve_host_path` applies the full lexical predicate twice — as written, and again
+    after canonicalisation.** That includes the general hidden-component rule, which
+    deliberately over-catches: a path resolving through `node_modules/.pnpm`, `~/.cache` or
+    `~/.local/share` is refused. Do not narrow it back to a list of "credential" directories.
+    That was tried, and allow-by-omission let `~/.local/bin` (write there and you own the
+    user's next shell command), `~/.password-store`, browser profiles and `~/.pki/nssdb`
+    through a planted symlink with a perfectly visible name. Over-refusing is the cheaper
+    mistake. Note the cost is real and has grown: of the four callers, the Files pane's two
+    are routine, and their path comes from a dialog — so an over-catch refuses a destination a
+    person actually chose (`~/.config` is the common one). Accepted, and not a reason to
+    narrow the rule, because the terminal drop and `download_container_backup` still take
+    their host path over IPC and this predicate is their only boundary.
+  - **OS drag-out is not here.** `tauri-plugin-drag`, `stage_container_file_for_drag` and its
+    host staging directory were held back for separate hardening and live on
     `hold/disk-and-dragout`. Do not re-add `drag:allow-start-drag` or a staging command
     without taking that work back whole: the plugin has no scope mechanism, so the grant lets
     a compromised webview start a drag on *any* host path the user can read, and the staging
@@ -126,6 +171,19 @@ docker exec stdout → tokio task → emit("terminal-output-{sessionId}") → li
   Beyond docker/project/settings/terminal: `inspect_commands.rs` (read-only views into a
   container — Claude sessions, installed capabilities, scheduler tasks), `auth_bridge_commands.rs`,
   `auth_token_commands.rs`.
+- **`file_viewer/`** — one window per click (`file-viewer-<n>`), a managed `ViewerRegistry`,
+  resolution by probing `/workspace/<p>` then `/workspace/<mount>/<p>` in one exec as `claude`,
+  polling by `sha256sum`, saves staged in `/tmp` and swapped in by a `sh` script as the container
+  user (spec §5 says why the archive API never writes to the target directory). Commands take
+  `window: tauri::Window`, gate on the label and act on the caller's own registry entry — no
+  viewer command accepts a path. Which window may *call* each command is the ACL's job: the
+  `file-viewer-*` capability grants exactly the five `viewer_*` commands (see `build.rs`).
+- **`build.rs` + `src/command_census.rs`** — the build declares a Tauri `AppManifest` from the
+  `generate_handler!` list and refuses to build unless every command has exactly one bare
+  `allow-*` grant in the capability file its name says it belongs to. The parser and rules are
+  in `command_census.rs`, compiled into both the build script and the test build, so they are
+  unit-tested; `the_generated_app_manifest_matches_the_handler_list` reads back what tauri
+  embedded. Design: `docs/superpowers/specs/2026-09-22-app-manifest-lockdown-design.md`.
 - **`auth_bridge/`** — Host-side loopback bridge so browser logins run *inside* a container can
   complete against the host browser. Discovers listeners by parsing `/proc/net/tcp{,6}` (the image
   has no `ss`/`netstat`/`lsof`), binds host `127.0.0.1` **only**, and tunnels in over the Docker
@@ -378,6 +436,26 @@ container is created once by a very long function where a dropped capability is
   existing toggle: the label fingerprints *the setting*, not the set of things the setting drives,
   so a project already at `true` gets no recreation at all on upgrade.
 
+### Keeping Claude Code current
+
+`claude update` runs in **two** places, and both are needed:
+
+- `container/entrypoint.sh` runs it once per container start, before any session exists.
+- `commands/terminal_commands.rs` (and its twin in `web_terminal/ws_handler.rs`) prepend it to the
+  command every Claude session launches with, because containers use a stop/start model and a
+  long-lived one would otherwise never re-check.
+
+Both are `timeout`-bounded and `|| echo`'d, so an offline or slow network delays a tab rather than
+failing it, and **both take the same `flock` on `/tmp/.triple-c-claude-update.lock`**. That lock is
+not tidiness: the entrypoint prints "container ready" only after its own update finishes, so
+starting a project and immediately opening a tab — or opening two tabs at once — otherwise runs two
+updaters against the same `~/.claude/bin`, and `|| echo` would hide a half-written install behind a
+friendly message one line before `exec claude` ran it. `-E 0` makes losing the race a success,
+because the holder just did the work. The per-session copy is what forced the non-Bedrock path from a bare `["claude", ...]`
+argv into a `bash -c` wrapper — the flags and the session name are interpolated into a shell
+string now, so **anything added there must go through `shell_quote_arg`**. Bash sessions are
+deliberately untouched.
+
 ### Container Lifecycle
 
 Containers use a **stop/start** model (not create/destroy). Installed packages persist across stops. The `.claude` config dir uses a named Docker volume (`triple-c-claude-config-{projectId}`), nested inside the home volume (`triple-c-home-{projectId}`), so OAuth tokens and Claude Code config survive container stop/start *and* container recreation.
@@ -401,6 +479,63 @@ security update. Migration is the non-destructive way out; Reset is the destruct
   bump: churn on the old base, and it would consume the "you should migrate" signal without
   migrating. `get_container_staleness` surfaces it; `migrate_project_to_base` acts on it.
 - **A missing lineage label means "unknown, probe instead", never "stale".**
+- **The snapshot image is not a checkpoint — never read its absence as "nothing to inspect".**
+  `commit_container_snapshot` runs only before a container is destroyed (a config-change recreate)
+  or inside a migration. **Never on stop.** So a project in daily use for a year can legitimately
+  have no `triple-c-snapshot-{id}:latest` at all, and one that has is stale by everything installed
+  since. `pick_probe_source` therefore reads a *stopped* container directly — commit its writable
+  layer to a unique `triple-c-probe-*` image, probe that, drop it — and ranks it **above** the snapshot,
+  for the same reason a running container already outranked it. Assuming a snapshot existed is what
+  made a stopped, never-recreated project report "no container or snapshot image yet" with its
+  container sitting right there, and left Update disabled on the projects furthest behind.
+- **`bollard` never gives you the image id back from a commit.** Its `Commit` response model
+  deserialises `"ID"`; the daemon sends `"Id"`, so `commit_container` returns `id: None` every time
+  (verified: bollard 0.18.1, Engine 29.6). Neither long-standing commit site notices because both
+  discard the response — but it means any commit you need a *reference* to has to be **tagged**.
+- **A tagged leftover is the one orphan no sweep can reach, so the probe image has its own reaper.**
+  `sweep_orphaned_snapshots` collects `dangling` + `triple-c.managed=true`; `reap_stale_migration_pins`
+  and `scrub_secrets_from_snapshots` both filter `triple-c-snapshot-*`. A `triple-c-probe-*` image is
+  tagged and so matches none of them, which would make a crashed probe a permanent multi-gigabyte
+  leak with no UI to find it. `reap_probe_images` runs at startup beside `reap_probe_containers` and
+  is **load-bearing, not tidying** — it is also what makes the probe image's unscrubbed writable
+  layer acceptable. Two rules it earned the hard way:
+  - **Age-gate it** (`PROBE_REAP_MIN_AGE_SECS`, same as the container reaper). `reference=` is
+    daemon-wide, so a second copy of the app has live probe images matching the glob.
+  - **Remove by tag, never by image id.** A `force` removal by id untags an image *everywhere*; a
+    fixture that tagged `alpine:latest` into this namespace deleted the user's alpine that way.
+- **Probe image names are unique per call, and must stay that way.** A stable per-container name was
+  tried: container ids do not survive a recreate, so most leftovers were stranded permanently, and
+  two concurrent probes fought over one tag — whichever finished first force-removed the image the
+  other was still reading, reporting a bogus `probe_error` on a healthy project. `get_container_staleness`
+  takes no `project_lock` claim (the migration banner needs it to answer *during* a migration), so
+  uniqueness is what makes overlapping probes safe.
+- **The stopped-container probe is cached per stop, and that is not an optimisation you may drop.**
+  `getContainerStaleness` is called from a `useEffect` that fires whenever the container settles, so
+  merely opening a stopped project's Overview probes it. Uncached that is a `docker commit` of the
+  whole writable layer per visit — measured at 44 s on a real project, against ~3 s for the snapshot
+  probe it replaced. `STOPPED_MANIFEST_CACHE` is keyed on the container's `FinishedAt`, which is
+  exact rather than merely plausible: nothing can write to a stopped container's writable layer, and
+  `FinishedAt` moves on every stop. A live test asserts the restart case, because a cache that
+  failed to invalidate would plan a migration against a filesystem the project no longer has.
+- **Do not "skip the probe when the project is not stale" to save that cost.** It was tried. The
+  deltas would be empty while `probeSettled` (`!probing && staleness && !probe_error`) stayed *true*,
+  which leaves the migrate action in the project menu enabled — that action is not gated on the
+  banner — so the pre-flight would report nothing to copy while the backend was told to copy
+  nothing. That is the exact hazard `ProjectHome.tsx`'s `canMigrate` comment already warns about.
+- **A failed stopped-container probe falls back to the snapshot whenever one exists.** Before this
+  feature a stopped project read its snapshot directly, so surfacing a commit failure where the
+  snapshot could have answered would make the banner *worse* than it was — and the failure modes are
+  exactly the ones where the fallback earns its keep: a full disk (the commit allocates the whole
+  writable layer; the snapshot probe allocates nothing) and a 409 from a concurrent claim.
+- **`get_container_staleness` never commits while the project is claimed.** It takes no
+  `project_lock` claim itself, deliberately — the banner has to answer *during* a migration — so it
+  reads `project_lock::held` instead and probes the snapshot rather than the container. The
+  collision is not symmetric: the probe losing is a retryable `probe_error`, but
+  `start_project_container` removes the old container with a hard `?`, so a remove that raced a
+  commit would fail the user's Start with an opaque error.
+- **An image's `Created` is the image's own, not its tag's.** Tagging an existing image gives you
+  that image's age; BuildKit stamps `docker build` output with a fixed epoch. Only `docker commit`
+  stamps *now* — which is what real probe images do, and what any fixture for them must do.
 - **`:latest` keeps pointing at the old lineage until the final commit.** That is what makes every
   crash before that point self-heal — `start_project_container` just recreates from the old
   snapshot. After the container swap, the new container's `triple-c.migration-state=in-progress`
@@ -466,9 +601,28 @@ Anthropic and Bedrock deliberately keep Claude Code's own defaults.
 
 - Frontend types in `lib/types.ts` must stay in sync with Rust structs in `models/`
 - Tauri commands are registered in `lib.rs` via `.invoke_handler(tauri::generate_handler![...])`
-- `capabilities/default.json` grants permissions for **plugin** commands only (`core:`, `dialog:`,
-  `store:`, `opener:`). Application commands registered through `generate_handler!` do **not**
-  need an entry there — adding one is not required and none exists for any app command.
+- **A new command needs three things:** `#[tauri::command]`, a `generate_handler!` entry in
+  `lib.rs`, and a bare `allow-<name-with-dashes>` entry in the one capability file for the
+  window that calls it — `viewer_*` commands in `capabilities/file-viewer.json`, everything else
+  in `capabilities/default.json`. `build.rs` declares a Tauri `AppManifest` from the handler list
+  (without one, tauri 2.11 does not apply the ACL to app commands at all) and fails `cargo
+  check`/`tauri build` on a missing, misspelled, duplicated or misfiled grant, a `deny-*`, or a
+  hand-written file under `permissions/`. `src/test/capabilities.test.ts` fails if code that runs
+  in a window imports a `tauri-commands.ts` wrapper that window is not granted. Only `_` becomes
+  `-` in the identifier; `permissions/autogenerated/` is generated and ignored, and
+  `gen/schemas/*.json` is regenerated by every build and committed.
+- **A new window needs its own top-level `capabilities/*.json`; never `webviews`/`remote`;
+  never inline.** `build.rs` only vouches for what `src/command_census.rs` reads — a top-level
+  `capabilities/*.json` file with a `windows` list — so it refuses to build on anything tauri
+  would load that the census can't check: a capability under a subdirectory or written as
+  `.toml`/`.json5`, a `webviews` or `remote` key in a capability file (either widens grants past
+  what `windows` says), `app.security.capabilities` declared inline in `tauri.conf.json`/any
+  `tauri.<platform>.conf.json`/`TAURI_CONFIG`, or a tauri config in a format it can't parse
+  (JSON5, TOML). OS/editor junk (`.DS_Store`, `Thumbs.db`, swap files) is recognised and skipped
+  rather than refused. Each failure names the check that failed, not just "capabilities do not
+  match generate_handler!". **Known limit:** adding a new `tauri.<platform>.conf.json` to a tree
+  that has already been built once only takes effect on a clean build or in CI — cargo's
+  incremental build has no reason to notice a file that did not exist on the previous build.
 - The `projects.json` file uses atomic writes (write to `.tmp`, then `rename()`). Corrupted files are backed up to `.bak`.
 - **Adding project state that changes the container?** `container_needs_recreation()` is entirely
   **label-based** — it does not diff the container's env. If a new setting affects the container's
@@ -489,6 +643,198 @@ Anthropic and Bedrock deliberately keep Claude Code's own defaults.
   `#[serde(default)]` on a `bool` yields `false`; follow the `default_full_permissions` pattern in
   `models/project.rs` for anything that should default to true.
 - Cross-platform paths: Docker socket is `/var/run/docker.sock` on Linux/macOS, `//./pipe/docker_engine` on Windows
+- A new local window needs its own capability file (`capabilities/file-viewer.json` is the
+  model), and `lib.rs`'s `on_window_event` stays guarded on `label() == "main"`.
+
+## Secrets
+
+**`scripts/scan-secrets.sh` refuses a commit that adds something shaped like a live
+credential.** Enable the hook once per clone with `npm run hooks` (from `app/`), which sets
+`core.hooksPath` to `.githooks`. A repository cannot configure its own hooks path — cloning it
+would then be enough to run its code — so this is opt-in everywhere, and `--no-verify` skips it.
+The `Secret Scan` workflow is the half nobody can bypass; it carries **no `paths:` filter**, on
+purpose, because the incident that prompted all this lived in `app/**` and `build.yml` only runs
+for `container/**`.
+
+Three rules, and the second half of the third is what keeps it usable: vendor-prefixed tokens
+(`ghp_`, `sk-`, `AKIA`, `xox`, …), `BEGIN … PRIVATE KEY` blocks, and an opaque literal assigned to
+a secret-shaped name. That last one needs **both** halves — the identifier must read as a
+credential *and* the whole literal must be hex or base64 with no word structure. Name-proximity
+alone flags `secure::get_project_secret(&id, "aws-secret-access-key")`, which is a keychain key
+name; the literal test is what excludes it. Measured against the tree: 0 false positives, and it
+catches the real incident (`9b2f4fe`) when replayed.
+
+A line ending `pragma: allowlist secret` is skipped. Make a fixture obviously fake before reaching
+for it.
+
+**Why this exists:** `the_custom_env_fingerprint_never_carries_the_value` used the maintainer's
+real Gitea **site-admin** token as its fixture — a test about secrets not escaping, leaking one. It
+survived 92 commits and fourteen days in the public GitHub mirror, past five audit rounds and two
+independent reviews, because every one of them read the code under change and this sat in a test
+nobody had reason to open. Fixtures are never live values; there is no case where they need to be.
+
+## Settings export/import
+
+`commands::settings_export_commands`, `storage::settings_crypto`, `models::settings_export`
+(triple-c#35). Exports the *host* environment — global `AppSettings` plus the global secrets that
+live in the OS keychain instead: the shared Claude Code OAuth login and the model gateway's two
+keys. Per-project settings, per-project secrets, and anything in a project's Docker volumes are
+deliberately out of scope — this is not a project backup.
+
+- **`AppSettings` is not entirely the non-secret shape it looks like, and a review of this feature
+  caught the one place that isn't.** `WebTerminalSettings::access_token` is a live bearer
+  credential for a server that binds every interface — exporting `AppSettings` wholesale would
+  have carried it along as if it were as inert as a port number, and importing it would have
+  applied `web_terminal.enabled` and the token together with no more warning than any other
+  setting, letting a crafted export silently stand up a LAN-listening terminal on the next launch.
+  `export_settings`/`apply_settings_import` carve this one field out into `ExportedSecrets`
+  instead, with the same "only overwrite what the import actually has" treatment as the other
+  three secrets — except "leave it alone" has to be done by hand in `apply_settings_import`, since
+  unlike the keychain secrets this one lives inside the `AppSettings` blob that gets replaced
+  wholesale. `SettingsImportPreview::enables_web_terminal` also exists because of this: `enabled`
+  and the token are independent fields, and "this turns on a listening service" must not hide
+  inside a generic "settings replaced" summary. Read this as the standing example of the class of
+  thing to keep checking for in this feature, not a one-off fixed bug — any other field that looks
+  like config but is actually a live credential would have the same problem.
+- **Encrypted because it can carry live credentials, not for appearance's sake.** Argon2id derives
+  a 256-bit key from the user's password (memory-hard — meaningfully resistant to GPU/ASIC
+  brute-forcing, unlike PBKDF2 at any reasonable iteration count), AES-256-GCM does the actual
+  encryption. A wrong password fails GCM's authentication tag rather than producing silent
+  garbage. The salt and nonce are not secret and are written in the clear in the file's own
+  header — the salt's job is only to make two exports of the same password derive different keys,
+  and the nonce's only requirement is per-encryption uniqueness, which a fresh random draw on
+  every export already gives it.
+- **The save/open dialogs are opened from Rust**, the same boundary `file_commands.rs`'s
+  `pick_save_path`/`pick_files_to_upload` draw and document at length: a frontend-driven dialog
+  handing Rust a host path string is the exact shape of bug that produced this app's past
+  criticals. `preview_settings_import` resolves the chosen path itself and remembers it
+  (`AppState::pending_settings_import`) so `apply_settings_import` re-reads the same file without
+  a path ever crossing back over IPC. It also pins a hash of the file's ciphertext next to that
+  path, and `apply_settings_import` refuses to proceed if the file on disk no longer matches it —
+  otherwise confirming a preview would not actually be binding on what gets applied, which matters
+  given this feature's own threat model: a file shared between people may sit in a synced or
+  otherwise shared directory that changes between the two calls.
+- **The decrypted payload is not cached between preview and apply — only the password is reused.**
+  The frontend holds the password in React state and passes it to both calls; nothing in Rust
+  holds decrypted plaintext — secrets included — in memory for longer than one command's
+  execution, so `apply_settings_import` always re-decrypts rather than reusing anything
+  `preview_settings_import` computed. `preview_settings_import` returns counts and presence flags
+  only (`SettingsImportPreview`), never a secret value, so it's safe to hand to the frontend and
+  render directly.
+- **Import replaces settings wholesale, but only writes secrets actually present in the file.**
+  An import is "restore this environment," so the settings half is a full replace, not a
+  field-by-field merge. Secrets are different on purpose: an absent secret in the export means
+  "the source machine never had this configured," not "delete this on import" — a user who wants
+  to clear a secret already has dedicated UI for that (signing out of shared auth, clearing the
+  gateway key). Secrets are restored *before* the settings replace runs, not after — replacing
+  settings is what triggers `reconcile_gateway`, and restoring the other way round leaves a real
+  window where a gateway recreation happens against the destination's old keys.
+- **A restored gateway secret nudges a running gateway container to recreate itself, even when
+  nothing about the gateway's *shape* changed.** `reconcile_gateway`'s `gateway_shape_changed` only
+  compares port/provider/base URL/models — deliberately, since that's what's rendered into the
+  container's config — so a secret-only change (same shape, new key) is invisible to it. Left
+  alone, a running container would keep serving the old key material indefinitely after an import
+  that restored a new one. `apply_settings_import` tracks whether either gateway secret was
+  actually written and, if the gateway is enabled and its container both exists and is running,
+  calls `docker::gateway::ensure_gateway_running` directly afterward — its own fingerprint already
+  includes the secret rotation id (`storage::secure::get_gateway_secret_version`), so it recreates
+  exactly when it should and no more.
+- **A keychain write failing during import is reported back, not only logged.** Each of the three
+  `secure::store_*` calls collects its error into `SettingsImportOutcome::secret_restore_warnings`
+  in addition to logging it — an import that silently restores two of three secrets but not the
+  third must not read as unqualified success just because the settings half of the import (which
+  runs after, and is validated before any of this) went through. `apply_settings_import` returns
+  `SettingsImportOutcome { settings, secret_restore_warnings }` rather than bare `AppSettings` for
+  this reason; `ImportSettingsModal` shows any warnings alongside the "Settings imported" message.
+- **The imported settings are validated *before* any secret is written, not just before the
+  settings replace.** `apply_settings_import` calls
+  `settings_commands::validate_settings_update(&current, &settings)` — the same checks
+  `update_settings` runs internally, pulled out into its own function specifically so this caller
+  can run them first — and only proceeds to the three keychain writes if that passes. A review
+  caught the earlier ordering: writing secrets first meant a rejected import (a bad env var name, a
+  disallowed host path) still left the keychain overwritten with the file's secrets while the
+  settings themselves stayed unchanged, a silently half-applied state the error message gave no
+  hint of.
+- **`read_and_decrypt` checks `format_version` before attempting to parse the full payload, not
+  after.** A version bump that isn't deserialize-compatible is exactly the case that check exists
+  for, and parsing the full struct first would fail on the shape mismatch before the version check
+  ever ran. Neither error path interpolates what `serde_json` actually says into the message
+  shown to the user — its type-mismatch errors quote the offending value inline, and the plaintext
+  here can hold a live credential.
+- **The 8-character password minimum is enforced in `export_settings` itself, not only in the
+  export modal.** The frontend minimum is a UX nudge; the Rust command is the actual boundary a
+  weak password has to cross, and Argon2id's memory-hardness buys little against an attacker who
+  can just try a short password directly. Measured with `.chars().count()` (Unicode scalar values)
+  rather than `.len()` (bytes), to stay as close as this pair of languages allows to the frontend's
+  `.length` check (UTF-16 code units) — the two only diverge on astral-plane characters. The
+  derived key and both plaintext buffers — the payload built for export, and whatever `decrypt`
+  recovers on import — are wrapped in `zeroize::Zeroizing` for the same reason every other secret
+  in this codebase gets handled carefully — cheap insurance (`zeroize` is already pulled in
+  transitively via `aes-gcm`) for material that exists only to hold or produce live credentials.
+- **The preview also discloses non-blank custom base URLs** (`global_ollama`, `global_llamacpp`,
+  `global_openai_compatible`, `gateway.api_base`) so an import that would redirect model traffic to
+  a different server is visible in the confirmation dialog rather than discovered later — these are
+  endpoints, not secrets, so `SettingsImportPreview` carries and `describeImport` renders the actual
+  URL rather than just a presence flag. `describeImportWarnings` additionally calls out a web
+  terminal token that arrives with the terminal left *off*: `start_web_terminal` only mints a fresh
+  token when none is already set, so a planted token would otherwise activate silently the next
+  time someone turns the terminal on, with no import-time signal that it wasn't freshly generated.
+- **The preview also discloses a custom Docker image, and warns on one every time — not just on
+  change.** `custom_image_name`/`image_source` weren't in scope for the base-URL disclosure above,
+  but a review pointed out they're a sharper version of the same problem: this is the image *every*
+  project container is created from (`models::container_config::resolve_image_name`), so a crafted
+  export pointing it at an attacker-controlled image is a path to running arbitrary code with
+  whatever a project's containers are allowed to reach, not merely a redirected API endpoint.
+  `describeImportWarnings` fires on `image_source == Custom` unconditionally rather than only when
+  it differs from the destination's current value, since re-importing the same risky configuration
+  is still worth surfacing every time a user confirms an import.
+- **Every free-form string a preview surfaces is sanitized and length-capped before it's built.**
+  `SettingsImportPreview::from_payload`'s `sanitize_for_preview` strips control characters and caps
+  at 100 characters (`MAX_PREVIEW_STRING_LEN`) for every base URL and the custom image name — a
+  review noted that, unlike the count- and boolean-derived fields the preview started with, these
+  are verbatim strings from a not-yet-trusted decrypted payload rendered directly into the
+  confirmation dialog. Unbounded, a single pathological value (very long, or holding embedded
+  newlines) could push the security warnings above the scroll fold in the dialog that exists
+  specifically to make them unmissable — the frontend's `<li>`/warning boxes also get `break-all`
+  as a second layer against the same failure mode.
+
+## Packaging
+
+Linux ships as **AppImage only**, built by `build-app.yml` (releases) and
+`build-app-preview.yml` (the PR check). The `.deb` and `.rpm` were dropped: two more artifacts to
+build and publish for an audience the AppImage already serves, and neither could self-update. The
+Linux job passes `--bundles appimage`; `tauri.conf.json` still says `"targets": "all"` so macOS and
+Windows are untouched.
+
+`scripts/finalize-appimage.sh` post-processes every AppImage, and both things it does are
+load-bearing. **It demotes the bundled `libwayland-client.so.0`** off the loader path, keeping it as
+a fallback for a host that has none: `libEGL_mesa.so.0` has a hard `DT_NEEDED` on that library, so a
+bundled copy older than the host's Mesa stops the EGL driver loading at all and the window comes up
+blank — measured on wayland 1.26 / Mesa 26.2.1 against a 22.04-built image. Do not "fix" this by
+bundling a newer wayland: the floor is set by the user's Mesa, which moves independently of our
+releases, so this is a host-coupled library like libGL and libdrm. **It also embeds AppStream
+metadata and update information**, without which an AppImage manager can adopt the app but never
+update it. The update URL points at a fixed `linux-latest` tag on the GitHub mirror
+(`scripts/publish-update-channel.sh`), never `releases/latest` — that follows whichever release is
+newest, and the backfill creates a GitHub release per Gitea tag including the `-win` and `-mac` ones
+that carry no AppImage. The script's post-repack assertions are the only test any of this has.
+
+**There is deliberately no Arch package.** A
+`triple-c-bin` `PKGBUILD` and a `publish-arch-package.yml` existed and were removed; they live on
+`hold/arch-packaging`. Do not re-add them without the piece that was always missing: the package
+was never on the AUR, so it was a manual `pacman -U` of a downloaded file — the same gesture as
+the AppImage, for a second artifact to keep working. Being `workflow_dispatch`-only it also
+reached 1 release in 28, while `HOW-TO-USE.md` told Arch users to download it from every release.
+An AUR account and its SSH key as a repo secret are what would make it worth having; until then
+the AppImage is the Arch story.
+
+`scripts/install-appimage.sh` is the desktop-integration half, and it exists because an AppImage
+has no installer: it extracts the bundled icons into `~/.local/share/icons/hicolor` and writes a
+`.desktop` entry. It **rewrites** the `Exec` line rather than copying the bundled entry — the
+bundled one is `Exec=triple-c`, which resolves only inside the AppImage's own mount, so a
+verbatim copy yields a launcher entry that starts nothing. It keeps `StartupWMClass` exactly as
+the bundle sets it, which is what lets the shell match the window to the entry. Extraction uses
+`--appimage-extract`, which needs no FUSE, so the script works before `fuse2` is installed.
 
 ## Testing
 

HOW-TO-USE.md

@@ -6,6 +6,7 @@ Triple-C (Claude-Code-Container) is a desktop application that runs Claude Code
 
 ## Table of Contents
 
+- [Installation](#installation)
 - [Prerequisites](#prerequisites)
 - [First Launch](#first-launch)
 - [The Interface](#the-interface)
@@ -32,6 +33,65 @@ Triple-C (Claude-Code-Container) is a desktop application that runs Claude Code
 
 ---
 
+## Installation
+
+Download the build for your platform from [GitHub Releases](https://github.com/shadowdao/triple-c/releases/latest).
+
+| Platform | File | Install |
+|----------|------|---------|
+| **Windows** | `Triple-C_<version>_x64-setup.exe` or `.msi` | Run the installer. |
+| **macOS** | `Triple-C_<version>_universal.dmg` | Open the `.dmg` and drag Triple-C to Applications. |
+| **Linux (all distributions)** | `Triple-C_<version>_amd64.AppImage` | `chmod +x` it, then run it directly. See the AppImage notes below. |
+
+> **macOS note:** The app is not signed or notarized. On first launch, macOS Gatekeeper may block it — right-click the app and select "Open" to bypass, or remove the quarantine attribute: `xattr -cr /Applications/Triple-C.app`.
+
+> **AppImage note:** Two things are worth knowing. Running an AppImage needs FUSE 2, which Arch and CachyOS do not install by default — `sudo pacman -S fuse2` once, or run it with `--appimage-extract-and-run` to sidestep FUSE entirely. And an AppImage is just an executable file: nothing registers it with the desktop, so it will not appear in your app launcher on its own. Run [`scripts/install-appimage.sh`](scripts/install-appimage.sh) to add a launcher entry and icons — see [Adding an AppImage to the app launcher](#adding-an-appimage-to-the-app-launcher).
+
+> **Linux is AppImage only.** The `.deb` and `.rpm` were dropped. They were a second and third artifact to build, test and publish for an audience already served by the one file that runs on every distribution — and unlike the AppImage they could not be kept up to date automatically. Older releases still carry them if you need one.
+
+> **Updates.** The AppImage carries update information, so an AppImage manager (Gear Lever, AppImageLauncher and similar) can adopt it and update it in place — pulling only the changed blocks rather than re-downloading 85 MB. It reads a fixed `linux-latest` tag on GitHub, so the URL never moves between versions.
+
+> **No Arch package.** There was a `triple-c-bin` `.pkg.tar.zst` attached to some releases, built by a maintainer-triggered workflow. It was never on the AUR, so installing it meant downloading a file and running `pacman -U` — no better than the AppImage — and being manual-only it reached 1 release in 28, which made the promise of it worse than not making it. The `PKGBUILD` and its workflow are preserved on the `hold/arch-packaging` branch if an AUR package is ever worth doing properly.
+
+### Adding an AppImage to the app launcher
+
+An AppImage is a single executable file and nothing else. It carries a `.desktop`
+entry and icons *inside* itself, but nothing on your system ever reads them,
+because nothing installed it — so it will not show up in your app launcher, and
+running it from a file manager gives you a generic icon in the taskbar.
+
+Put the AppImage somewhere stable first — `~/Apps` or `~/.local/bin`, not
+`~/Downloads` — because the launcher entry points at wherever the file is:
+
+```bash
+mkdir -p ~/Apps
+mv ~/Downloads/Triple-C_*_amd64.AppImage ~/Apps/
+./scripts/install-appimage.sh ~/Apps/Triple-C_0.4.17_amd64.AppImage
+```
+
+That copies the bundled icons into `~/.local/share/icons/hicolor` and writes
+`~/.local/share/applications/triple-c.desktop` pointing at the file you named.
+No sudo, nothing outside your home directory, and the AppImage itself is never
+copied or moved. To remove the entry again:
+
+```bash
+./scripts/install-appimage.sh --uninstall
+```
+
+The script rewrites the `Exec` line rather than reusing the bundled `.desktop`
+verbatim: the bundled one says `Exec=triple-c`, which resolves only inside the
+running AppImage's own mount, so a launcher entry copied straight out of the
+bundle would appear in the menu and then fail to start anything.
+
+Two follow-ups worth knowing:
+
+- **Upgrading.** The entry names one specific file. If you replace the AppImage
+  with a newer version under a different filename, re-run the script against the
+  new one. Keeping a stable name (`~/Apps/Triple-C.AppImage`) avoids this.
+- **The icon may not appear until you log out.** That is the desktop shell's
+  icon cache, not a failed install — see
+  [App Icon Missing After Installing (Linux)](#app-icon-missing-after-installing-linux).
+
 ## Prerequisites
 
 ### Docker
@@ -183,7 +243,7 @@ Anthropic-backend project uses that token without its own login. See
 │             │  │                                                  │  │
 │             │  └──────────────────────────────────────────────────┘  │
 ├─────────────┴────────────────────────────────────────────────────────┤
-│  2 project(s) · 1 running · 2 terminal(s)          Jump to Current ↓ │
+│  2 project(s) · 1 running · 2 terminal(s)                      Notes │
 └──────────────────────────────────────────────────────────────────────┘
 ```
 
@@ -208,8 +268,8 @@ Anthropic-backend project uses that token without its own login. See
 - **Main area** — Shows the active tab: a Project Home view or an xterm.js terminal. With no tabs
   open you get a welcome screen with Docker/image/project readiness checks.
 - **StatusBar** — Counts of total projects, running containers and open terminal sessions; the
-  **Jump to Current ↓** button when a terminal is scrolled up; and the microphone button when
-  speech-to-text is enabled.
+  **🖱 Mouse captured — release** button while a program in the terminal is holding the mouse; the
+  **Notes** toggle; and the microphone button when speech-to-text is enabled.
 
 ---
 
@@ -228,7 +288,7 @@ buttons. Below that are six tabs:
 | **Sessions** | Past Claude Code conversations stored on this project's config volume, each with a **Resume** button |
 | **Automation** | The scheduled tasks running inside this container — see [Automation & Scheduled Tasks](#automation--scheduled-tasks) |
 | **Config** | All per-project configuration — see [Project Configuration](#project-configuration) |
-| **Files** | Browse, download and upload files inside the container |
+| **Files** | Browse, view and rename files inside the container, and move files between it and your own machine — see [Files](#files) |
 | **Browser** | Watch — and take over — the browser Claude is driving with Playwright, see [The Browser Tab](#the-browser-tab) |
 
 ### Sessions
@@ -351,7 +411,7 @@ it. The sidebar row carries only the two hover controls.
 | **Force stop** | Project Home header | Starting / Stopping | Interrupts a transition that is stuck |
 | **Open Claude Terminal** | Project Home header; sidebar hover control; `Ctrl+T` | Running | Opens a new Claude Code terminal tab |
 | **Shell** | Project Home header | Running | Opens a bash login shell tab in the container (no Claude Code) |
-| **Files** | Project Home header, and the **Files** tab | Running | Switches to the Files tab to browse, download and upload files |
+| **Files** | Project Home header, and the **Files** tab | Running | Switches to the Files tab to browse, view and rename files inside the container, upload files into it and save one back out |
 | **Config** | The **Config** tab | Always | Per-project configuration (most fields need the container stopped) |
 | **Back up container** | **⋯** overflow menu | A container exists | Saves a `.tar.gz` archive of the container to a location you choose |
 | **Reset container…** | **⋯** overflow menu | Stopped or Error | Destroys the container, snapshot image and both volumes, then recreates from the base image (wipes `~/.claude`) — asks first |
@@ -615,18 +675,27 @@ The **Claude Code settings** editor, also at the bottom of the Config tab, confi
 
 | Setting | What It Does |
 |---------|-------------|
-| **TUI Mode** | Set to **Fullscreen** for flicker-free alt-screen rendering (uses `CLAUDE_CODE_NO_FLICKER=1`) |
-| **Effort Level** | Controls reasoning depth: **Low** (fast, less thorough), **Medium**, **High** (deep reasoning) |
-| **Focus Mode** | Collapses tool output to one-line summaries, showing only the prompt and final response |
-| **Thinking Summaries** | Shows Claude's thinking process as summaries during responses |
-| **Session Recap** | Provides context when returning to a session after being away |
-| **Auto-Scroll Disabled** | Disables auto-scroll when in fullscreen TUI mode |
+| **TUI Mode** | **Automatic** lets Claude Code choose; **Classic** pins the main-screen renderer; **Fullscreen** pins the flicker-free alt-screen one |
+| **Effort Level** | Reasoning depth: **Low**, **Medium**, **High**, **Extra high** |
+| **Focus Mode** | Summarises tool *calls* to one line each, showing the last prompt and the final response. **Needs the fullscreen renderer** — set TUI Mode to Fullscreen or this does nothing |
+| **Thinking Summaries** | Shows Claude's thinking as summaries rather than a collapsed stub |
+| **Session Recap** | A one-line recap when you return to the terminal after a few minutes away. **On by default** — the switch is how you turn it off |
+| **Auto-Scroll** | Follows new output to the bottom in fullscreen rendering. On by default |
 | **Env Scrub** | Strips credentials from subprocess environments for security |
-| **Prompt Caching (1h)** | Enables 1-hour prompt cache TTL instead of the default 5 minutes |
+| **Prompt Caching (1h)** | Requests a 1-hour prompt cache TTL instead of the default 5 minutes |
 
-Per-project settings override global defaults set in Settings. If all settings are at their defaults, no configuration is injected.
+Each switch has three states on a project: **Global** (follow Settings), **On**, and **Off**. Off is a
+real choice — it overrides a global On, which a project could not previously do.
 
-> These settings map to Claude Code environment variables and `~/.claude/settings.json` entries. Changes require stopping and restarting the container to take effect.
+> These map to Claude Code environment variables and `~/.claude/settings.json` keys, and are applied
+> when the container starts. Changing one stops and recreates the container.
+>
+> **Two caveats on an existing project.** Changing any of these recreates the container, and a
+> recreation commits a new image layer — so flipping switches repeatedly costs disk. And
+> **TUI Mode, Effort Level, Focus Mode and Session Recap cannot be returned to Global** until the
+> project's base image is updated: those four are cleared by *removing* a key, and an older image's
+> startup script ignores the instruction to remove it. Update the base image from the project's
+> Overview tab first. The other switches work on any image.
 
 ### MCP Servers
 
@@ -1155,22 +1224,89 @@ Programs inside the container can copy text to your host clipboard. When a conta
 
 You can paste images from your clipboard into the terminal (Ctrl+V / Cmd+V). The image is uploaded to the container as `/tmp/clipboard_<timestamp>.png` and the file path is injected into the terminal input so Claude Code can reference it. A toast notification confirms the upload.
 
-### Jump to Current
+### Scrolling
 
-When you scroll up in the terminal to review previous output, a **Jump to Current** button appears in the bottom-right corner. Click it to scroll back to the latest output.
+Scrolling is the terminal's own: scroll up to read back and it holds position, scroll to the
+bottom and it follows new output again. There is no follow toggle — an earlier **Following /
+Paused** control and a **Jump to Current** button were retired once they stopped doing anything
+useful, because Claude Code draws its interface on the alternate screen, which has no scrollback
+for them to act on.
+
+### When the mouse stops working
+
+Some programs ask the terminal for the mouse, so that clicks and drags go to the program instead
+of selecting text. If one of them exits without handing the mouse back, the terminal looks stuck:
+you cannot select text, and stray characters can appear as you move the pointer.
+
+A **🖱 Mouse captured — release** button appears in the status bar whenever a program holds the
+mouse. Click it, or press **Ctrl+Shift+X**, to take the mouse back. Nothing is sent into the
+container — only the terminal's own state is reset.
+
+Note that holding the mouse is normal for programs like `htop`, `vim` and Claude Code itself, so
+the button is showing most of the time you are in one. It is there for when a program exits
+without handing the mouse back and the terminal is left stuck; releasing while a program is still
+running just takes the mouse away from that program.
+
+To select text *without* taking the mouse back, hold **Shift** while dragging — or **Option** on
+macOS.
 
 ### Files
 
-The **Files** tab of Project Home browses inside a running container. You can:
+The **Files** tab of Project Home browses inside a running container, and moves files between it
+and your own machine. You can:
 
-- **Browse** the container filesystem, starting at `/workspace`, with breadcrumb navigation
-- **Save to host…** — copy any file out to a location you pick. This is the way to get a file out
-  of a container; there is one button per file entry, and the file viewer offers it too
-- **Upload file** from your host into the current container directory — or **drop files straight
-  onto the pane** from your desktop, which uploads them into the directory on screen
+- **Browse** the container filesystem, starting at `/workspace`, with breadcrumb navigation.
+  Double-click a folder to open it, or the `..` row to go up; the arrow keys, Home and End move
+  between rows and Enter opens the selected one
+- **View** a file — double-click it, or press Enter. Text files and images render in a read-only
+  viewer
+- **Rename** an entry, from the row's Rename button or by pressing `F2`. A rename never moves a
+  file between folders
+- **New folder** in the directory on screen
+- **Upload…**, from the toolbar, to copy files from your machine into the directory on screen
+- **Save to host…**, from a file's own row, to write that one file out to your machine
 - **Refresh** the directory listing at any time
 
-The listing shows file names, sizes, and modification dates.
+The listing shows file names, sizes, and modification dates, and marks symbolic links.
+
+#### Getting files in and out
+
+**Upload…** opens a file dialog on your machine, and whatever you choose is copied into the
+directory currently on screen. Uploaded files arrive owned by you inside the container, not by
+root. You can pick several files in one dialog; each is handled on its own, so if a folder or an
+over-sized file is among them, it is named in the message and the rest still arrive. Uploads are
+capped at **256 MB per file** — for anything larger, mount the folder into the project instead and
+skip the copying altogether.
+
+**Save to host…** does the reverse, for one file: a save dialog opens, you choose where the file
+goes, and it is written there. The button sits on the file's own row, and only on files. For a
+whole directory, use **Back up container** in Project Home's **⋯** overflow menu, which writes a
+`.tar.gz` of the workspace and the container's `~/.claude` config to a location you choose — that
+is still the right tool for a tree.
+
+Dragging a file from your desktop and **dropping it onto the Terminal tab** works too, and is often
+the quickest way in when you are already typing: the file is copied into the container and its path
+is typed into the terminal for you, ready to hand to Claude Code. (The whole terminal pane is a
+drop target, including its *Following* toggle.) The Files pane itself is not a drop target.
+
+Both dialogs are opened by Triple-C itself rather than by the page you are looking at. The page
+cannot name a place on your machine — it can only ask for a dialog — and nothing is read or written
+until you pick somewhere in it. Closing a dialog without choosing is not an error: nothing happens,
+and nothing is said about it.
+
+Every one of these routes refuses a location whose path passes through a hidden *folder* — anything
+with a component beginning with `.`, such as `~/.ssh`, `~/.cache` or `~/.local/share` — or a system
+location, and it checks both the path as written and where it points after any symbolic links. That
+rule catches more than it strictly needs to, so now and then it will refuse a place you genuinely
+meant, `~/.config` among them. The refusal is a plain sentence saying so; choose a visible location
+such as `~/Documents` or `~/Downloads`.
+
+The *file's own name* is a different matter, and dotfiles are fine: `.env`, `.gitignore` and the
+rest save normally, since you chose the name in the save dialog yourself. Only the folders on the
+way are judged.
+
+If you already keep the project in a folder mounted into the container, the simplest answer is
+usually none of the above: edit the file on your host and it is already inside.
 
 ### Terminal Rendering
 
@@ -1216,10 +1352,14 @@ change. Remember that a headless run cannot answer a permission prompt, so in an
 **Bypass** a task may stop early when Claude Code asks for approval; the run log records the mode
 that was used.
 
-### Creating Tasks (In the Container)
+### Creating Tasks
 
-There is no "add task" form in the app. Create tasks from a terminal in the container — either type
-the commands yourself in a **Shell** session, or just ask Claude to do it.
+The quickest route is the **New task** button on a project's **Automation** tab, which gives you a
+form for the name, the schedule and the prompt.
+
+You can also create tasks from a terminal in the container — type the commands yourself in a
+**Shell** session, or just ask Claude to do it. That is the better route when you want Claude to
+work out the schedule or the prompt for you, and it is what the rest of this section covers.
 
 ### Create a Recurring Task
 
@@ -1478,3 +1618,9 @@ cp ~/.claude.json ~/.claude.json.bak && jq 'with_entries(select(.key | startswit
 ```
 
 This backs up your config and removes the corrupted marketplace entries. Claude Code will re-download them cleanly on the next startup.
+
+### App Icon Missing After Installing (Linux)
+
+If Triple-C's icon shows as generic or blank right after installing — in the app menu, taskbar, and window titlebar alike — **log out and back in.**
+
+Desktop shells (GNOME Shell, KDE Plasma) cache the list of installed apps and their resolved icons in memory when the shell starts, for performance. A freshly installed package's icon files land on disk correctly and its install hooks do rebuild the on-disk icon cache, but an already-running shell doesn't always notice — on X11 there used to be a way to soft-restart just the shell (GNOME's Alt+F2 → `r`) to force a reload, but under Wayland the shell *is* the compositor, so restarting it means ending the session. Logging out and back in starts a fresh shell that reads the current on-disk state, which picks the icon up.

README.md

@@ -24,7 +24,7 @@ This file is the architectural tour: what each subsystem is and why it works the
 - [Permission Modes](#permission-modes)
 - [Containers](#containers) — lifecycle, base-image migration, mounts, CA certificates, sibling containers
 - [Models and Authentication](#models-and-authentication) — backends, model aliases, gateway, shared token
-- [Bridges to the Host](#bridges-to-the-host) — URL relay, auth bridge, browser view
+- [Bridges to the Host](#bridges-to-the-host) — URL relay, auth bridge, browser view, host file transfers
 - [Inside a Project](#inside-a-project) — capability tiles, Mission Control, web terminal, speech-to-text
 - [Key Files](#key-files) · [CSS / Styling Notes](#css--styling-notes) · [Container Image](#container-image)
 
@@ -105,7 +105,7 @@ configuration. Per-project configuration lives in the Config tab rather than in
 | **Sessions** | Past Claude Code conversations read from the config volume, with **Resume** |
 | **Automation** | The container's `triple-c-scheduler` tasks — create, edit, enable/disable, run now, read logs, remove, and completion notifications |
 | **Config** | Workspace (name, folders), Model (backend), Access (SSH, git, env vars, port mappings), Runtime (permission mode, sandbox, Docker access, Mission Control, instructions, Claude Code settings) |
-| **Files** | Browse, download and upload files inside the container |
+| **Files** | Browse, view, rename and create folders inside the container, upload host files into the directory on screen, and save one file back out to the host — see [Host File Transfers](#host-file-transfers). A whole tree still comes out through **Back up container** |
 | **Browser** | Watch and take over the Playwright browser inside the container — see [Browser View](#browser-view) |
 
 Container start/stop progress is reported inline (on the sidebar row and in the Project Home
@@ -442,6 +442,39 @@ per project.
   binds, but never `@playwright/cli`, which is the viewer. It is what binds sessions automatically
   once Playwright is present — not a setup route.
 
+### Host File Transfers
+
+Four routes move files across the boundary: **Upload…** and the per-row **Save to host…** in the
+Files tab, a file dropped onto the Terminal tab, and **Back up container**. All four share one path
+policy in `commands/file_commands.rs`.
+
+- **The OS dialogs are opened by Rust, not by the webview.** `upload_files_to_container` and
+  `download_container_file` drive `tauri-plugin-dialog` themselves and take nothing but a project
+  id and a container-side path; `FilesTab.tsx` imports no dialog plugin and `useFileManager`'s
+  `uploadFiles` takes no argument at all. The web UI can ask for a dialog, and that is the whole of
+  its influence over where a file comes from or goes — it cannot name a host path as an *input*.
+  This is a boundary rather than a convention: a dialog the page itself opens is only as trustworthy
+  as the page. Be precise about the limit, though — host paths still travel *outward* in error text,
+  canonical ones included, so this closes the inbound direction and not both.
+- **The dialog's pre-filled name is sanitized, because a container authored it.** On Windows the
+  save dialog parses its name box as a path, and a container can name a file
+  `..\..\Users\you\…\Word\STARTUP\x.dotm` — one POSIX segment, so nothing upstream objects.
+  `suggested_save_name` replaces every separator and every character NTFS refuses, so the string
+  cannot be a path on any platform this ships to.
+- **One policy for every host path.** A source or destination whose path passes through a hidden
+  folder (`~/.ssh`, `~/.cache`, `~/.local/share`, anything dot-prefixed) or a system location is
+  refused, and the check is applied both to the path as written and to what it resolves to after
+  symlinks. It over-catches deliberately, so it will occasionally refuse somewhere a person
+  genuinely meant — `~/.config`, say — and the refusal is a sentence naming the folder that tripped
+  it, not an errno.
+- **Uploads are capped at 256 MB per file**; past that the answer is a mount, not a copy. One
+  dialog's selection is handled file by file, so a folder or an oversized file among the selection
+  is reported by name and does not stop the others. Uploaded files land owned by the container user,
+  not root. A cancelled dialog is silent — `Ok(None)`, not an error.
+- **`download_container_file` is one file and files only** — no button on a folder row. A directory
+  is what `download_container_backup` is for. There is no drop target on the Files pane; the
+  Terminal tab keeps the one it has.
+
 ## Inside a Project
 
 ### Container Introspection (Capability Tiles)
@@ -495,7 +528,7 @@ Triple-C includes optional speech-to-text powered by [Faster Whisper](https://gi
 | `app/src/components/layout/TopBar.tsx` | Hosts MainTabs + Docker/Image status indicators + Help |
 | `app/src/components/layout/MainTabs.tsx` | The single main-area tab strip (Project Home + terminal tabs), pointer-event drag reordering |
 | `app/src/components/layout/Sidebar.tsx` | Responsive sidebar (25% width, min 224px, max 320px), collapsible to an icon rail |
-| `app/src/components/layout/StatusBar.tsx` | Project/terminal counts, Jump to Current, STT mic |
+| `app/src/components/layout/StatusBar.tsx` | Project/terminal counts, Notes toggle, STT mic |
 | `app/src/components/projects/ProjectRow.tsx` | Select-only sidebar row; opens Project Home, with hover start/stop and terminal controls |
 | `app/src/components/projects/ProjectList.tsx` | Project list in sidebar |
 | `app/src/components/projects/PermissionModeControl.tsx` | Plan / Default / Accept Edits / Bypass segmented control |
@@ -513,7 +546,7 @@ Triple-C includes optional speech-to-text powered by [Faster Whisper](https://gi
 | `app/src/components/projects/home/AutomationTab.tsx` | Scheduler tasks: create, toggle, run now, logs, remove, notifications |
 | `app/src/components/projects/home/TaskEditorModal.tsx` | Create/edit a scheduled task; `taskValidation.ts` holds the cron and schedule rules |
 | `app/src/components/projects/home/ConfigTab.tsx` | Config sections (Workspace, Model, Access, Runtime) |
-| `app/src/components/projects/home/FilesTab.tsx` | File browser (browse, download, upload) |
+| `app/src/components/projects/home/FilesTab.tsx` | Container-side file browser (navigate, view, rename, new folder) plus **Upload…** and per-row **Save to host…**; imports no dialog plugin — the dialogs are Rust's |
 | `app/src/components/projects/home/BrowserTab.tsx` | Browser view pane: detect, install, watch, take over, pop out |
 | `app/src/components/projects/home/OpenPageDialog.tsx` | Open a URL in the container's browser at a chosen viewport |
 | `app/src/components/projects/home/ContainerMigrationBanner.tsx` | Base-image staleness banner, migration progress, resume/rollback |
@@ -536,7 +569,7 @@ Triple-C includes optional speech-to-text powered by [Faster Whisper](https://gi
 | `app/src/hooks/useTerminal.ts` | Terminal session management (claude and bash modes) |
 | `app/src/hooks/useProjectActions.ts` | Start/stop/reset/backup and terminal-opening helpers |
 | `app/src/hooks/useContainerMigration.ts` | Staleness polling, migration run, resume and rollback |
-| `app/src/hooks/useFileManager.ts` | File manager operations (list, download, upload) |
+| `app/src/hooks/useFileManager.ts` | File browser operations (list, navigate, rename, mkdir) and the host transfers (upload, save one file out); never handles a host path |
 | `app/src/hooks/useClaudeAuth.ts` | Shared-token status and acquisition |
 | `app/src/hooks/useSTT.ts` | Speech-to-text recording, transcription, and container management |
 | `app/src/lib/urlRelay.ts` | Host-side relay validation: OSC 7777 parsing, http/https allowlist, rate limiting |
@@ -547,7 +580,7 @@ Triple-C includes optional speech-to-text powered by [Faster Whisper](https://gi
 | File | Purpose |
 |---|---|
 | `app/src-tauri/src/docker/container.rs` | Container creation, mounts, env vars, labels, recreation checks, `remove_project_volumes` |
-| `app/src-tauri/src/docker/exec.rs` | `create_attached_exec()` — the single attached-exec path; file upload/download via tar |
+| `app/src-tauri/src/docker/exec.rs` | `create_attached_exec()` — the single attached-exec path; one-shot execs and single-file tar building |
 | `app/src-tauri/src/docker/image.rs` | Image building/pulling |
 | `app/src-tauri/src/docker/migration.rs` | Base-image migration: manifest capture, delta computation, crash-recovery state machine |
 | `app/src-tauri/src/docker/ca_certs.rs` | CA certificate discovery, `.crt` renaming, fingerprinting |
@@ -561,7 +594,7 @@ Triple-C includes optional speech-to-text powered by [Faster Whisper](https://gi
 | `app/src-tauri/src/commands/inspect_commands.rs` | Read-only container views: sessions, capabilities, scheduler tasks |
 | `app/src-tauri/src/commands/auth_token_commands.rs` | `claude setup-token` flow, redaction, keychain storage |
 | `app/src-tauri/src/commands/auth_bridge_commands.rs` | Auth bridge enable/status commands |
-| `app/src-tauri/src/commands/file_commands.rs` | File manager Tauri commands (list, download, upload) |
+| `app/src-tauri/src/commands/file_commands.rs` | Container-side file commands (list, read, rename, mkdir), the host transfers `upload_files_to_container` and `download_container_file` — each opening its own OS dialog here in Rust — plus `download_container_backup`, and the hidden-folder path policy all of them share |
 | `app/src-tauri/src/commands/stt_commands.rs` | STT start/stop/transcribe Tauri commands |
 | `app/src-tauri/src/commands/web_terminal_commands.rs` | Web terminal start/stop/status Tauri commands |
 | `app/src-tauri/src/models/project.rs` | Project struct (backend, `PermissionMode`, Docker access, Claude Code settings, Mission Control, auth bridge, browser view, CA path, shared-token opt-out) |

ROADMAP.md

@@ -58,7 +58,7 @@ choice it never asked about.
 
 Also covered: per-project auth backends (Anthropic OAuth, Bedrock incl. SSO refresh,
 Ollama, OpenAI-compatible), user-level `CLAUDE.md` composition, `claude update` on every
-container start, terminal ergonomics (OAuth URL detection, OSC 52 clipboard, image paste,
+container start *and* before every Claude session launches, terminal ergonomics (OAuth URL detection, OSC 52 clipboard, image paste,
 file drag-drop, STT), the web terminal, and workspace backup.
 
 ---

TECHNICAL.md

@@ -62,10 +62,13 @@ Tauri uses a Rust backend paired with a web-based frontend rendered by the OS-na
 Implementation gotchas for the terminal view and its global controls (merged in PR #7, `terminal-layout-statusbar`):
 
 - **xterm padding lives on a wrapper, never the host.** FitAddon measures the same element that `term.open()` mounts into, so any padding on that host element makes the grid overhang and clip its rightmost column / bottom row. Padding must live on a **wrapper `div`**; the xterm host fills it with no padding of its own. Do not reintroduce padding on the host element in `TerminalView.tsx`.
-- **STT mic and "Jump to Current" live in the global `StatusBar`, not per-terminal overlays.** There is a single `useSTT` instance in `App.tsx` bound to the active session. `Ctrl+Shift+M` routes through the Zustand store (`sttToggle`).
+- **The STT mic lives in the global `StatusBar`, not a per-terminal overlay.** There is a single `useSTT` instance in `App.tsx` bound to the active session. `Ctrl+Shift+M` routes through the Zustand store (`sttToggle`).
 - **Recording is pinned to where it started.** The STT transcript targets `recordingSessionIdRef` (the session recording began in), **not** the live active session — switching tabs mid-recording must not misroute the transcript.
-- **"Jump to Current" state is written only by the active terminal.** The active `TerminalView` surfaces `terminalAtBottom` and `scrollActiveToBottom` through the store; only the active terminal writes them, and they are cleared on its unmount.
-- **Set store function values via object-merge, not the updater form** — `set({ fn: value })`, not `set(state => ...)` — when publishing action callbacks (like `scrollActiveToBottom`) into the Zustand store.
+- **Scrolling is left to xterm, and the "Following" / "Jump to Current" controls that used to drive it are gone.** They were built for the normal buffer. Claude Code draws on the *alternate* screen, which has no scrollback, so in a Claude tab `viewportY` always equalled `baseY`, `isAtBottom` was permanently true and neither control could ever do anything — which is what made them look broken. **They did still work in `bash` tabs**, which run `bash -l` on the normal buffer; removing them is a real behaviour change there, and the justification is that xterm's native follow already covers it, not that nothing was lost. The manual `scrollToBottom()` on every write went with them — it fought that native behaviour, which follows the tail while the viewport is at the bottom and holds position while you read further up. `scrollToBottom()` remains only on activate and after a refit, and **both sample `viewportY >= baseY` before the `fit()`** so they re-anchor only a viewport that was already on the tail: the ResizeObserver fires for the Notes dock, the sidebar drag and any window resize, none of which are a reason to yank a reader to the bottom.
+- **A program that grabs the mouse and dies must be escapable without closing the tab.** A TUI sets DECSET `?1000`/`?1002`/`?1003` and, if it exits without resetting them, xterm keeps routing clicks, drags and (under `?1003`) every pointer *move* to the PTY — text selection dies and escape bytes flood the prompt. `TerminalView` reconciles a badge against `term.modes.mouseTrackingMode` **in the `term.write()` callback**: the mode only changes because the container printed a sequence, so one check per write catches every transition with no polling. Releasing writes the resets through `term.write`, **never `sendInput`** — the reset belongs to xterm's parser and must not reach the container, or a still-live TUI would simply re-grab the mouse on its next repaint. Bound to the control and to `Ctrl+Shift+X`, because the failure being recovered from is the pointer not working.
+- **The release control lives in the `StatusBar`, not over the terminal.** Mouse tracking is the *normal* steady state of every mouse-driven TUI — htop, vim, lazygit and Claude Code all set `?1000`/`?1002` — so a badge painted at `absolute top-2 right-4 z-50` would be on screen for the entire life of those programs and would swallow clicks aimed at that program's own top-right corner, silently killing its mouse with no undo. The active `TerminalView` publishes `terminalMouseCaptured` and `releaseActiveMouse` through the store instead, the same way `terminalHasSelection` and `sttToggle` already do.
+- **`macOptionClickForcesSelection: true` is set, and without it macOS has no force-select at all.** `SelectionService.shouldForceSelection` is `isMac ? altKey && macOptionClickForcesSelection : shiftKey`, and the option defaults to `false` — so the "hold Shift to select while a program holds the mouse" escape hatch is Shift everywhere else and **Option** on macOS, and existed on macOS only once this was turned on.
+- **Set store function values via object-merge, not the updater form** — `set({ fn: value })`, not `set(state => ...)` — when publishing action callbacks (like `sttToggle`) into the Zustand store.
 
 ### bollard (Docker API)
 
@@ -412,13 +415,12 @@ triple-c/
 │
 ├── .gitea/
 │   └── workflows/
-│       ├── build-app.yml          # Build Tauri app (Linux/macOS/Windows)
-│       ├── build-app-preview.yml  # Preview builds
-│       ├── build.yml              # Build container image (multi-arch)
-│       ├── build-stt.yml          # Build the STT image
-│       ├── sync-release.yml       # Mirror releases to GitHub
-│       ├── backfill-releases.yml  # Bulk copy releases to GitHub
-│       └── cleanup-releases.yml   # Prune old releases
+│       ├── build-app.yml            # Build Tauri app (Linux/macOS/Windows); mirrors releases to GitHub inline
+│       ├── build-app-preview.yml    # Preview builds
+│       ├── build.yml                # Build container image (multi-arch)
+│       ├── build-stt.yml            # Build the STT image
+│       ├── backfill-releases.yml    # Bulk copy releases to GitHub
+│       ├── cleanup-releases.yml     # Prune old releases
 │
 └── app/                           # Tauri v2 desktop application
     ├── package.json               # React, xterm.js, zustand, tailwindcss
@@ -436,7 +438,7 @@ triple-c/
     │   │   ├── useClaudeAuth.ts   # Shared token status + acquisition
     │   │   ├── useContainerProgress.ts # container-progress events → inline progress
     │   │   ├── useDocker.ts       # Docker status, image build/pull
-    │   │   ├── useFileManager.ts  # File browser operations
+    │   │   ├── useFileManager.ts  # File browser operations + host transfers
     │   │   ├── useInstallHelper.ts # Guided Docker installation
     │   │   ├── useKeyboardShortcuts.ts # Ctrl+T / Ctrl+Shift+W / Ctrl+Tab / Ctrl+1..9
     │   │   ├── useProjectActions.ts # Start/stop/reset/backup, open terminals
@@ -464,7 +466,7 @@ triple-c/
     │       │   │   ├── SessionsTab.tsx   # Past Claude sessions + Resume
     │       │   │   ├── AutomationTab.tsx # Scheduler tasks + notifications
     │       │   │   ├── ConfigTab.tsx     # Config section host
-    │       │   │   ├── FilesTab.tsx      # In-container file browser
+    │       │   │   ├── FilesTab.tsx      # In-container file browser, upload / save to host
     │       │   │   ├── CapabilityTiles.tsx # Read-only capability counts
     │       │   │   ├── format.ts         # Age / size / uptime formatting
     │       │   │   └── config/           # WorkspaceSection, ModelSection,
@@ -504,7 +506,7 @@ triple-c/
             │   ├── auth_token_commands.rs   # claude setup-token flow, redaction, keychain
             │   ├── aws_commands.rs          # AWS profile/region discovery
             │   ├── docker_commands.rs       # Docker status, image ops
-            │   ├── file_commands.rs         # File browser (list/download/upload)
+            │   ├── file_commands.rs         # File browser + host transfers (Rust-opened dialogs)
             │   ├── help_commands.rs         # Serves HOW-TO-USE.md to the Help dialog
             │   ├── inspect_commands.rs      # Sessions, capabilities, scheduler tasks
             │   ├── install_helper_commands.rs # Guided Docker installation

app/package-lock.json

@@ -8,6 +8,21 @@
       "name": "triple-c",
       "version": "0.4.0",
       "dependencies": {
+        "@codemirror/commands": "^6.11.1",
+        "@codemirror/lang-css": "^6.3.1",
+        "@codemirror/lang-html": "^6.4.12",
+        "@codemirror/lang-javascript": "^6.2.5",
+        "@codemirror/lang-json": "^6.0.2",
+        "@codemirror/lang-markdown": "^6.5.2",
+        "@codemirror/lang-python": "^6.2.1",
+        "@codemirror/lang-rust": "^6.0.2",
+        "@codemirror/lang-yaml": "^6.1.3",
+        "@codemirror/language": "^6.12.4",
+        "@codemirror/legacy-modes": "^6.5.4",
+        "@codemirror/search": "^6.7.2",
+        "@codemirror/state": "^6.7.6",
+        "@codemirror/view": "^6.43.13",
+        "@lezer/highlight": "^1.2.3",
         "@tauri-apps/api": "^2",
         "@tauri-apps/plugin-dialog": "^2.7.0",
         "@tauri-apps/plugin-opener": "^2.5.3",
@@ -413,6 +428,204 @@
         "specificity": "bin/cli.js"
       }
     },
+    "node_modules/@codemirror/autocomplete": {
+      "version": "6.20.3",
+      "resolved": "https://registry.npmjs.org/@codemirror/autocomplete/-/autocomplete-6.20.3.tgz",
+      "integrity": "sha512-tlosUqb+3BbxCxZdu4tKeRghPFC+QM7q4X5YhKV2eCmPG+1r2F3f4AaSz5sCrFqUtX4Jh20VFTKecl16MgiV9g==",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/language": "^6.0.0",
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.17.0",
+        "@lezer/common": "^1.0.0"
+      }
+    },
+    "node_modules/@codemirror/commands": {
+      "version": "6.11.1",
+      "resolved": "https://registry.npmjs.org/@codemirror/commands/-/commands-6.11.1.tgz",
+      "integrity": "sha512-O/4hG3SC1YwcmQ0d2UVNDs+AsaNWd1iHVxbTeEBuqH+6bExAiPK3iS/BvpY6rZGURALv4ZD3sIgcCmRvw3ehBg==",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/language": "^6.0.0",
+        "@codemirror/state": "^6.7.0",
+        "@codemirror/view": "^6.27.0",
+        "@lezer/common": "^1.1.0"
+      }
+    },
+    "node_modules/@codemirror/lang-css": {
+      "version": "6.3.1",
+      "resolved": "https://registry.npmjs.org/@codemirror/lang-css/-/lang-css-6.3.1.tgz",
+      "integrity": "sha512-kr5fwBGiGtmz6l0LSJIbno9QrifNMUusivHbnA1H6Dmqy4HZFte3UAICix1VuKo0lMPKQr2rqB+0BkKi/S3Ejg==",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/autocomplete": "^6.0.0",
+        "@codemirror/language": "^6.0.0",
+        "@codemirror/state": "^6.0.0",
+        "@lezer/common": "^1.0.2",
+        "@lezer/css": "^1.1.7"
+      }
+    },
+    "node_modules/@codemirror/lang-html": {
+      "version": "6.4.12",
+      "resolved": "https://registry.npmjs.org/@codemirror/lang-html/-/lang-html-6.4.12.tgz",
+      "integrity": "sha512-pw2ReWKUqSkbvh76RAT4NYxiogRu+PWkR2ukAwO9uOgrm8uipkzjtKKtNpyeAQwHOqxEeSvAXZ6vr3AfyB9y/w==",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/autocomplete": "^6.0.0",
+        "@codemirror/lang-css": "^6.0.0",
+        "@codemirror/lang-javascript": "^6.0.0",
+        "@codemirror/language": "^6.4.0",
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.17.0",
+        "@lezer/common": "^1.0.0",
+        "@lezer/css": "^1.1.0",
+        "@lezer/html": "^1.3.12"
+      }
+    },
+    "node_modules/@codemirror/lang-javascript": {
+      "version": "6.2.5",
+      "resolved": "https://registry.npmjs.org/@codemirror/lang-javascript/-/lang-javascript-6.2.5.tgz",
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+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/autocomplete": "^6.0.0",
+        "@codemirror/language": "^6.6.0",
+        "@codemirror/lint": "^6.0.0",
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.17.0",
+        "@lezer/common": "^1.0.0",
+        "@lezer/javascript": "^1.0.0"
+      }
+    },
+    "node_modules/@codemirror/lang-json": {
+      "version": "6.0.2",
+      "resolved": "https://registry.npmjs.org/@codemirror/lang-json/-/lang-json-6.0.2.tgz",
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+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/language": "^6.0.0",
+        "@lezer/json": "^1.0.0"
+      }
+    },
+    "node_modules/@codemirror/lang-markdown": {
+      "version": "6.5.2",
+      "resolved": "https://registry.npmjs.org/@codemirror/lang-markdown/-/lang-markdown-6.5.2.tgz",
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+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/autocomplete": "^6.7.1",
+        "@codemirror/lang-html": "^6.0.0",
+        "@codemirror/language": "^6.3.0",
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.0.0",
+        "@lezer/common": "^1.2.1",
+        "@lezer/markdown": "^1.0.0"
+      }
+    },
+    "node_modules/@codemirror/lang-python": {
+      "version": "6.2.1",
+      "resolved": "https://registry.npmjs.org/@codemirror/lang-python/-/lang-python-6.2.1.tgz",
+      "integrity": "sha512-IRjC8RUBhn9mGR9ywecNhB51yePWCGgvHfY1lWN/Mrp3cKuHr0isDKia+9HnvhiWNnMpbGhWrkhuWOc09exRyw==",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/autocomplete": "^6.3.2",
+        "@codemirror/language": "^6.8.0",
+        "@codemirror/state": "^6.0.0",
+        "@lezer/common": "^1.2.1",
+        "@lezer/python": "^1.1.4"
+      }
+    },
+    "node_modules/@codemirror/lang-rust": {
+      "version": "6.0.2",
+      "resolved": "https://registry.npmjs.org/@codemirror/lang-rust/-/lang-rust-6.0.2.tgz",
+      "integrity": "sha512-EZaGjCUegtiU7kSMvOfEZpaCReowEf3yNidYu7+vfuGTm9ow4mthAparY5hisJqOHmJowVH3Upu+eJlUji6qqA==",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/language": "^6.0.0",
+        "@lezer/rust": "^1.0.0"
+      }
+    },
+    "node_modules/@codemirror/lang-yaml": {
+      "version": "6.1.3",
+      "resolved": "https://registry.npmjs.org/@codemirror/lang-yaml/-/lang-yaml-6.1.3.tgz",
+      "integrity": "sha512-AZ8DJBuXGVHybpBQhmZtgew5//4hv3tdkXnr3vDmOUMJRuB6vn/uuwtmTOTlqEaQFg3hQSVeA90NmvIQyUV6FQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/autocomplete": "^6.0.0",
+        "@codemirror/language": "^6.0.0",
+        "@codemirror/state": "^6.0.0",
+        "@lezer/common": "^1.2.0",
+        "@lezer/highlight": "^1.2.0",
+        "@lezer/lr": "^1.0.0",
+        "@lezer/yaml": "^1.0.0"
+      }
+    },
+    "node_modules/@codemirror/language": {
+      "version": "6.12.4",
+      "resolved": "https://registry.npmjs.org/@codemirror/language/-/language-6.12.4.tgz",
+      "integrity": "sha512-1q4PaT+o6PbgpkJt4Q8Fv5XJxTy4FUZ4MWETtyiDw3J0Pyr9E2vqcKL+k9wcvjNTIsauxvE7OfmWj3FRPHQ76A==",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.23.0",
+        "@lezer/common": "^1.5.0",
+        "@lezer/highlight": "^1.0.0",
+        "@lezer/lr": "^1.0.0",
+        "style-mod": "^4.0.0"
+      }
+    },
+    "node_modules/@codemirror/legacy-modes": {
+      "version": "6.5.4",
+      "resolved": "https://registry.npmjs.org/@codemirror/legacy-modes/-/legacy-modes-6.5.4.tgz",
+      "integrity": "sha512-/cZr6qZyl08iYNLGsJ862CXXNI51LryRFRE40ejgoIjXZz0C1rGkD3/Ek5jM/8w1ceRjqtt4qx/KLMh4zBTgew==",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/language": "^6.0.0"
+      }
+    },
+    "node_modules/@codemirror/lint": {
+      "version": "6.9.7",
+      "resolved": "https://registry.npmjs.org/@codemirror/lint/-/lint-6.9.7.tgz",
+      "integrity": "sha512-28/+iWLYxKxsvGYhSYL7zaCZqLz5+FFFDq9tVsvGv9kv8RY4fFAchJ5WX9M3YrrRlTIsECjsXPqeNgnSmNP2dg==",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.42.0",
+        "crelt": "^1.0.5"
+      }
+    },
+    "node_modules/@codemirror/search": {
+      "version": "6.7.2",
+      "resolved": "https://registry.npmjs.org/@codemirror/search/-/search-6.7.2.tgz",
+      "integrity": "sha512-gUYkYhT2+n/+VGZ+8EzE5WFkYZUZYm1VOKDudIsNqh42uRVQJ0a6Yss9sdKT3MeOYfuL1N6AZA57oza0Oyr0LA==",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.37.0",
+        "crelt": "^1.0.5"
+      }
+    },
+    "node_modules/@codemirror/state": {
+      "version": "6.7.6",
+      "resolved": "https://registry.npmjs.org/@codemirror/state/-/state-6.7.6.tgz",
+      "integrity": "sha512-kAz+AncRtKuIknedxT1bq4XwXv4UowhbkHU1myPrtVb/jZtImWuV5BXzv5vK6i3kYACsdiZiQKFQQ5Mq7elW8w==",
+      "license": "MIT",
+      "dependencies": {
+        "@marijn/find-cluster-break": "^1.0.0"
+      }
+    },
+    "node_modules/@codemirror/view": {
+      "version": "6.43.13",
+      "resolved": "https://registry.npmjs.org/@codemirror/view/-/view-6.43.13.tgz",
+      "integrity": "sha512-sihaFrUzAsYBQsL9J2t69y8nfMQGwcYmggAZsk+kjPbjYZMyuf2hU8tUNTZ+P+isb6XRr8JE22TZlJxBoVdH1A==",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/state": "^6.7.0",
+        "crelt": "^1.0.6",
+        "style-mod": "^4.1.0",
+        "w3c-keyname": "^2.2.4"
+      }
+    },
     "node_modules/@csstools/color-helpers": {
       "version": "6.0.2",
       "resolved": "https://registry.npmjs.org/@csstools/color-helpers/-/color-helpers-6.0.2.tgz",
@@ -1055,6 +1268,123 @@
         "@jridgewell/sourcemap-codec": "^1.4.14"
       }
     },
+    "node_modules/@lezer/common": {
+      "version": "1.5.2",
+      "resolved": "https://registry.npmjs.org/@lezer/common/-/common-1.5.2.tgz",
+      "integrity": "sha512-sxQE460fPZyU3sdc8lafxiPwJHBzZRy/udNFynGQky1SePYBdhkBl1kOagA9uT3pxR8K09bOrmTUqA9wb/PjSQ==",
+      "license": "MIT"
+    },
+    "node_modules/@lezer/css": {
+      "version": "1.3.8",
+      "resolved": "https://registry.npmjs.org/@lezer/css/-/css-1.3.8.tgz",
+      "integrity": "sha512-EJn1zcL9qoDptief6ipWKZKLiOpXkxSe0+t8CH9oiMVcZlq7NBWrjCqnc/41EIjeo/ITj1gFFiATdTkaJDL+Og==",
+      "license": "MIT",
+      "dependencies": {
+        "@lezer/common": "^1.2.0",
+        "@lezer/highlight": "^1.0.0",
+        "@lezer/lr": "^1.3.0"
+      }
+    },
+    "node_modules/@lezer/highlight": {
+      "version": "1.2.3",
+      "resolved": "https://registry.npmjs.org/@lezer/highlight/-/highlight-1.2.3.tgz",
+      "integrity": "sha512-qXdH7UqTvGfdVBINrgKhDsVTJTxactNNxLk7+UMwZhU13lMHaOBlJe9Vqp907ya56Y3+ed2tlqzys7jDkTmW0g==",
+      "license": "MIT",
+      "dependencies": {
+        "@lezer/common": "^1.3.0"
+      }
+    },
+    "node_modules/@lezer/html": {
+      "version": "1.3.13",
+      "resolved": "https://registry.npmjs.org/@lezer/html/-/html-1.3.13.tgz",
+      "integrity": "sha512-oI7n6NJml729m7pjm9lvLvmXbdoMoi2f+1pwSDJkl9d68zGr7a9Btz8NdHTGQZtW2DA25ybeuv/SyDb9D5tseg==",
+      "license": "MIT",
+      "dependencies": {
+        "@lezer/common": "^1.2.0",
+        "@lezer/highlight": "^1.0.0",
+        "@lezer/lr": "^1.0.0"
+      }
+    },
+    "node_modules/@lezer/javascript": {
+      "version": "1.5.5",
+      "resolved": "https://registry.npmjs.org/@lezer/javascript/-/javascript-1.5.5.tgz",
+      "integrity": "sha512-sWg4yX1J6XW67AaAynVt0iwF0M5c+np36TEu+P2ifAJ8haRYvHnWDV28r1jdwnJehWCwXECutAUy56K4RBZIyg==",
+      "license": "MIT",
+      "dependencies": {
+        "@lezer/common": "^1.2.0",
+        "@lezer/highlight": "^1.1.3",
+        "@lezer/lr": "^1.3.0"
+      }
+    },
+    "node_modules/@lezer/json": {
+      "version": "1.0.3",
+      "resolved": "https://registry.npmjs.org/@lezer/json/-/json-1.0.3.tgz",
+      "integrity": "sha512-BP9KzdF9Y35PDpv04r0VeSTKDeox5vVr3efE7eBbx3r4s3oNLfunchejZhjArmeieBH+nVOpgIiBJpEAv8ilqQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@lezer/common": "^1.2.0",
+        "@lezer/highlight": "^1.0.0",
+        "@lezer/lr": "^1.0.0"
+      }
+    },
+    "node_modules/@lezer/lr": {
+      "version": "1.4.10",
+      "resolved": "https://registry.npmjs.org/@lezer/lr/-/lr-1.4.10.tgz",
+      "integrity": "sha512-rnCpTIBafOx4mRp43xOxDJbFipJm/c0cia/V5TiGlhmMa+wsSdoGmUN3w5Bqrks/09Q/D4tNAmWaT8p6NRi77A==",
+      "license": "MIT",
+      "dependencies": {
+        "@lezer/common": "^1.0.0"
+      }
+    },
+    "node_modules/@lezer/markdown": {
+      "version": "1.7.2",
+      "resolved": "https://registry.npmjs.org/@lezer/markdown/-/markdown-1.7.2.tgz",
+      "integrity": "sha512-iTkYvoVcKt3WkeL7qUDyXHONZEwLio4wj8KTNi2dnjQEXBZKMV63BpQrPqfsM+OkvuRbiSTAcycYAsQzLhRNoQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@lezer/common": "^1.5.0",
+        "@lezer/highlight": "^1.0.0"
+      }
+    },
+    "node_modules/@lezer/python": {
+      "version": "1.1.19",
+      "resolved": "https://registry.npmjs.org/@lezer/python/-/python-1.1.19.tgz",
+      "integrity": "sha512-MhQIURHRytsNzP/YXnqpYKW6la6voAH3kyplTOOiCdjyFY6cWWGFVmYVdHIPrElqSDf4iCDktQCockB9FxuhzQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@lezer/common": "^1.2.0",
+        "@lezer/highlight": "^1.0.0",
+        "@lezer/lr": "^1.0.0"
+      }
+    },
+    "node_modules/@lezer/rust": {
+      "version": "1.0.3",
+      "resolved": "https://registry.npmjs.org/@lezer/rust/-/rust-1.0.3.tgz",
+      "integrity": "sha512-XxErOjZzQ7yJt1agUT4fu9qQvESZ3acgoxpPaPTPOiUx+duCjaVAtZGFIgphkHxlN05djdVAIOy/wItShMEjqQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@lezer/common": "^1.2.0",
+        "@lezer/highlight": "^1.0.0",
+        "@lezer/lr": "^1.0.0"
+      }
+    },
+    "node_modules/@lezer/yaml": {
+      "version": "1.0.4",
+      "resolved": "https://registry.npmjs.org/@lezer/yaml/-/yaml-1.0.4.tgz",
+      "integrity": "sha512-2lrrHqxalACEbxIbsjhqGpSW8kWpUKuY6RHgnSAFZa6qK62wvnPxA8hGOwOoDbwHcOFs5M4o27mjGu+P7TvBmw==",
+      "license": "MIT",
+      "dependencies": {
+        "@lezer/common": "^1.2.0",
+        "@lezer/highlight": "^1.0.0",
+        "@lezer/lr": "^1.4.0"
+      }
+    },
+    "node_modules/@marijn/find-cluster-break": {
+      "version": "1.0.4",
+      "resolved": "https://registry.npmjs.org/@marijn/find-cluster-break/-/find-cluster-break-1.0.4.tgz",
+      "integrity": "sha512-Wy0V7+SGUjnF9/TkiM1hKVDPj7jKXduPNboMVtHTA8dySMURWqfg/JZ9E2Sq8JgSJmkl7k7Qe9FLeMSrSraWmQ==",
+      "license": "MIT"
+    },
     "node_modules/@rolldown/pluginutils": {
       "version": "1.0.0-beta.27",
       "resolved": "https://registry.npmjs.org/@rolldown/pluginutils/-/pluginutils-1.0.0-beta.27.tgz",
@@ -2523,6 +2853,12 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/crelt": {
+      "version": "1.0.7",
+      "resolved": "https://registry.npmjs.org/crelt/-/crelt-1.0.7.tgz",
+      "integrity": "sha512-aK6BbWfhf4U/wCcLHKPJl/xa6VkVstRaPywWtMKGwuOLc/wZTyQYuoxgvZnNsBvv7Kg3YTBQYYBCggcviQczuA==",
+      "license": "MIT"
+    },
     "node_modules/css-tree": {
       "version": "3.1.0",
       "resolved": "https://registry.npmjs.org/css-tree/-/css-tree-3.1.0.tgz",
@@ -3599,6 +3935,12 @@
         "node": ">=8"
       }
     },
+    "node_modules/style-mod": {
+      "version": "4.1.4",
+      "resolved": "https://registry.npmjs.org/style-mod/-/style-mod-4.1.4.tgz",
+      "integrity": "sha512-XXWIQt633/EpAFx8aZDOTjBzrCaGmhvEQlQo6MVPfa2OzO2cWo+4hV9h+6UkHYlXGfy+ODXKUdP7Pthmcu5ATw==",
+      "license": "MIT"
+    },
     "node_modules/symbol-tree": {
       "version": "3.2.4",
       "resolved": "https://registry.npmjs.org/symbol-tree/-/symbol-tree-3.2.4.tgz",
@@ -3925,6 +4267,12 @@
         }
       }
     },
+    "node_modules/w3c-keyname": {
+      "version": "2.2.8",
+      "resolved": "https://registry.npmjs.org/w3c-keyname/-/w3c-keyname-2.2.8.tgz",
+      "integrity": "sha512-dpojBhNsCNN7T82Tm7k26A6G9ML3NkhDsnw9n/eoxSRlVBB4CEtIQ/KTCLI2Fwf3ataSXRhYFkQi3SlnFwPvPQ==",
+      "license": "MIT"
+    },
     "node_modules/w3c-xmlserializer": {
       "version": "5.0.0",
       "resolved": "https://registry.npmjs.org/w3c-xmlserializer/-/w3c-xmlserializer-5.0.0.tgz",

app/package.json

@@ -9,9 +9,25 @@
     "preview": "vite preview",
     "tauri": "tauri",
     "test": "vitest run",
-    "test:watch": "vitest"
+    "test:watch": "vitest",
+    "hooks": "git -C .. config core.hooksPath .githooks && echo \"pre-commit secret scan enabled\""
   },
   "dependencies": {
+    "@codemirror/commands": "^6.11.1",
+    "@codemirror/lang-css": "^6.3.1",
+    "@codemirror/lang-html": "^6.4.12",
+    "@codemirror/lang-javascript": "^6.2.5",
+    "@codemirror/lang-json": "^6.0.2",
+    "@codemirror/lang-markdown": "^6.5.2",
+    "@codemirror/lang-python": "^6.2.1",
+    "@codemirror/lang-rust": "^6.0.2",
+    "@codemirror/lang-yaml": "^6.1.3",
+    "@codemirror/language": "^6.12.4",
+    "@codemirror/legacy-modes": "^6.5.4",
+    "@codemirror/search": "^6.7.2",
+    "@codemirror/state": "^6.7.6",
+    "@codemirror/view": "^6.43.13",
+    "@lezer/highlight": "^1.2.3",
     "@tauri-apps/api": "^2",
     "@tauri-apps/plugin-dialog": "^2.7.0",
     "@tauri-apps/plugin-opener": "^2.5.3",

app/src-tauri/Cargo.lock

@@ -8,6 +8,41 @@ version = "2.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "320119579fcad9c21884f5c4861d16174d0e06250625266f50fe6898340abefa"
 
+[[package]]
+name = "aead"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d122413f284cf2d62fb1b7db97e02edb8cda96d769b16e443a4f6195e35662b0"
+dependencies = [
+ "crypto-common",
+ "generic-array",
+]
+
+[[package]]
+name = "aes"
+version = "0.8.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b169f7a6d4742236a0a00c541b845991d0ac43e546831af1249753ab4c3aa3a0"
+dependencies = [
+ "cfg-if",
+ "cipher",
+ "cpufeatures",
+]
+
+[[package]]
+name = "aes-gcm"
+version = "0.10.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "831010a0f742e1209b3bcea8fab6a8e149051ba6099432c8cb2cc117dec3ead1"
+dependencies = [
+ "aead",
+ "aes",
+ "cipher",
+ "ctr",
+ "ghash",
+ "subtle",
+]
+
 [[package]]
 name = "aho-corasick"
 version = "1.1.4"
@@ -47,6 +82,18 @@ version = "1.0.102"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7f202df86484c868dbad7eaa557ef785d5c66295e41b460ef922eca0723b842c"
 
+[[package]]
+name = "argon2"
+version = "0.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3c3610892ee6e0cbce8ae2700349fcf8f98adb0dbfbee85aec3c9179d29cc072"
+dependencies = [
+ "base64ct",
+ "blake2",
+ "cpufeatures",
+ "password-hash",
+]
+
 [[package]]
 name = "async-broadcast"
 version = "0.7.2"
@@ -280,6 +327,12 @@ version = "0.22.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "72b3254f16251a8381aa12e40e3c4d2f0199f8c6508fbecb9d91f575e0fbb8c6"
 
+[[package]]
+name = "base64ct"
+version = "1.8.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2af50177e190e07a26ab74f8b1efbfe2ef87da2116221318cb1c2e82baf7de06"
+
 [[package]]
 name = "bit-set"
 version = "0.8.0"
@@ -310,6 +363,15 @@ dependencies = [
  "serde_core",
 ]
 
+[[package]]
+name = "blake2"
+version = "0.10.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "46502ad458c9a52b69d4d4d32775c788b7a1b85e8bc9d482d92250fc0e3f8efe"
+dependencies = [
+ "digest",
+]
+
 [[package]]
 name = "block-buffer"
 version = "0.10.4"
@@ -569,6 +631,16 @@ dependencies = [
  "windows-link 0.2.1",
 ]
 
+[[package]]
+name = "cipher"
+version = "0.4.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "773f3b9af64447d2ce9850330c473515014aa235e6a783b02db81ff39e4a3dad"
+dependencies = [
+ "crypto-common",
+ "inout",
+]
+
 [[package]]
 name = "combine"
 version = "4.6.7"
@@ -694,6 +766,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "78c8292055d1c1df0cce5d180393dc8cce0abec0a7102adb6c7b1eef6016d60a"
 dependencies = [
  "generic-array",
+ "rand_core 0.6.4",
  "typenum",
 ]
 
@@ -753,6 +826,15 @@ version = "0.0.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "52560adf09603e58c9a7ee1fe1dcb95a16927b17c127f0ac02d6e768a0e25bc1"
 
+[[package]]
+name = "ctr"
+version = "0.9.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0369ee1ad671834580515889b80f2ea915f23b8be8d0daa4bbaf2ac5c7590835"
+dependencies = [
+ "cipher",
+]
+
 [[package]]
 name = "darling"
 version = "0.20.11"
@@ -923,6 +1005,7 @@ checksum = "9ed9a281f7bc9b7576e61468ba615a66a5c8cfdff42420a70aa82701a3b1e292"
 dependencies = [
  "block-buffer",
  "crypto-common",
+ "subtle",
 ]
 
 [[package]]
@@ -1550,6 +1633,16 @@ dependencies = [
  "syn 2.0.117",
 ]
 
+[[package]]
+name = "ghash"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f0d8a4362ccb29cb0b265253fb0a2728f592895ee6854fd9bc13f2ffda266ff1"
+dependencies = [
+ "opaque-debug",
+ "polyval",
+]
+
 [[package]]
 name = "gio"
 version = "0.18.4"
@@ -2114,6 +2207,15 @@ dependencies = [
  "cfb",
 ]
 
+[[package]]
+name = "inout"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "879f10e63c20629ecabbb64a8010319738c66a5cd0c29b02d63d272b03751d01"
+dependencies = [
+ "generic-array",
+]
+
 [[package]]
 name = "ipnet"
 version = "2.11.0"
@@ -2831,6 +2933,12 @@ version = "1.21.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "42f5e15c9953c5e4ccceeb2e7382a716482c34515315f7b03532b8b4e8393d2d"
 
+[[package]]
+name = "opaque-debug"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c08d65885ee38876c4f86fa503fb49d7b507c2b62552df7c70b2fce627e06381"
+
 [[package]]
 name = "open"
 version = "5.3.3"
@@ -2913,6 +3021,17 @@ dependencies = [
  "windows-link 0.2.1",
 ]
 
+[[package]]
+name = "password-hash"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "346f04948ba92c43e8469c1ee6736c7563d71012b17d40745260fe106aac2166"
+dependencies = [
+ "base64ct",
+ "rand_core 0.6.4",
+ "subtle",
+]
+
 [[package]]
 name = "pathdiff"
 version = "0.2.3"
@@ -3194,6 +3313,18 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "polyval"
+version = "0.6.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9d1fe60d06143b2430aa532c94cfe9e29783047f06c0d7fd359a9a51b729fa25"
+dependencies = [
+ "cfg-if",
+ "cpufeatures",
+ "opaque-debug",
+ "universal-hash",
+]
+
 [[package]]
 name = "potential_utf"
 version = "0.1.4"
@@ -5149,6 +5280,8 @@ dependencies = [
 name = "triple-c"
 version = "0.4.0"
 dependencies = [
+ "aes-gcm",
+ "argon2",
  "axum",
  "base64 0.22.1",
  "bollard",
@@ -5173,7 +5306,9 @@ dependencies = [
  "tauri-plugin-opener",
  "tokio",
  "tower-http",
+ "url",
  "uuid",
+ "zeroize",
 ]
 
 [[package]]
@@ -5287,6 +5422,16 @@ version = "0.2.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ebc1c04c71510c7f702b52b7c350734c9ff1295c464a03335b00bb84fc54f853"
 
+[[package]]
+name = "universal-hash"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fc1de2c688dc15305988b563c3854064043356019f97a4b46276fe734c4f07ea"
+dependencies = [
+ "crypto-common",
+ "subtle",
+]
+
 [[package]]
 name = "untrusted"
 version = "0.9.0"

app/src-tauri/Cargo.toml

@@ -36,6 +36,13 @@ tower-http = { version = "0.6", features = ["cors"] }
 base64 = "0.22"
 rand = "0.9"
 local-ip-address = "0.6"
+argon2 = "0.5"
+aes-gcm = "0.10"
+zeroize = "1"
+# WHATWG URL parsing for `url_open`'s re-validation of URLs arriving from the
+# container. Already in the tree transitively (reqwest), and the point of
+# using it rather than hand-rolling is parity with the frontend's `new URL()`.
+url = "2"
 
 [dev-dependencies]
 # `test-util` (not part of tokio's `full`) lets the auto-start retry tests run
@@ -44,6 +51,8 @@ tokio = { version = "1", features = ["full", "test-util"] }
 
 [build-dependencies]
 tauri-build = { version = "2", features = [] }
+# build.rs reads capabilities/*.json to cross-check them against generate_handler!.
+serde_json = "1"
 
 [features]
 default = ["custom-protocol"]

app/src-tauri/build.rs

@@ -1,3 +1,208 @@
-fn main() {
-    tauri_build::build()
+//! Declares the Tauri `AppManifest`, so every app command is ACL-gated per window, and refuses
+//! to build unless every registered command is granted in exactly one capability file — the
+//! file whose `windows` the command's name says it belongs to. Without an app manifest, tauri
+//! 2.11 skips the ACL for app commands entirely (`webview/mod.rs:1794`), so any local window
+//! could call any command.
+//!
+//! Because the census can only vouch for what it reads, the build also stops on any capability
+//! tauri would load that the census does not: anything in `capabilities/` other than a
+//! top-level `*.json`, a `webviews`/`remote` key, `app.security.capabilities` in a tauri config
+//! or `TAURI_CONFIG`, and any hand-written file under `permissions/`.
+//!
+//! The parser and the rules live in `src/command_census.rs`, which `cargo test` also compiles,
+//! so they have unit tests. Spec: `docs/superpowers/specs/2026-09-22-app-manifest-lockdown-design.md`.
+
+#[path = "src/command_census.rs"]
+mod command_census;
+
+use std::path::Path;
+
+/// Stops the build. `what` names the check that failed, so a malformed capability file, a
+/// stray entry or a hand-written permission does not read as a grant/handler mismatch.
+fn fail(what: &str, problems: &[String], hint: &str) -> ! {
+    eprintln!();
+    eprintln!(
+        "{what} ({} problem{}):",
+        problems.len(),
+        if problems.len() == 1 { "" } else { "s" }
+    );
+    for p in problems {
+        eprintln!("  - {p}");
+    }
+    eprintln!();
+    eprintln!("{hint}");
+    eprintln!();
+    std::process::exit(1);
+}
+
+const LAYOUT_HINT: &str = "Every capability is a top-level capabilities/*.json file with a \
+    `windows` list and no `webviews` or `remote`, and no capability is declared anywhere else \
+    (tauri.conf.json, TAURI_CONFIG, subdirectories, .toml/.json5). The census in \
+    src/command_census.rs can only vouch for what it reads.";
+
+fn file_name(path: &Path) -> String {
+    path.file_name()
+        .expect("a directory entry has a file name")
+        .to_string_lossy()
+        .into_owned()
+}
+
+fn main() {
+    // tauri-build already emits rerun-if-changed for `capabilities`, `permissions` and the
+    // tauri config files, and rerun-if-env-changed for TAURI_CONFIG.
+    println!("cargo:rerun-if-changed=src/lib.rs");
+    println!("cargo:rerun-if-changed=src/command_census.rs");
+
+    let lib_rs = std::fs::read_to_string("src/lib.rs")
+        .expect("build.rs runs with CWD = src-tauri, so src/lib.rs must be readable");
+    let Some(commands) = command_census::registered_commands(&lib_rs) else {
+        fail(
+            "missing generate_handler! block",
+            &["src/lib.rs has no `generate_handler![ … ])` block to derive the AppManifest from"
+                .to_string()],
+            "build.rs derives the AppManifest from that block; see src/command_census.rs.",
+        );
+    };
+
+    check_tauri_config();
+    let files = read_capabilities();
+
+    let problems = command_census::check(&commands, &files);
+    if !problems.is_empty() {
+        fail(
+            "capabilities do not match generate_handler!",
+            &problems,
+            "Every app command needs exactly one bare `allow-<command-with-dashes>` grant: \
+             `viewer_*` commands in capabilities/file-viewer.json, everything else in \
+             capabilities/default.json. See src/command_census.rs.",
+        );
+    }
+
+    prune_permissions(&commands);
+
+    // `AppManifest::commands` takes `&'static [&'static str]` and the struct is `Copy`, so
+    // there is no owned form; leaking is fine in a process that exits right after.
+    let leaked: Vec<&'static str> = commands
+        .into_iter()
+        .map(|c| &*Box::leak(c.into_boxed_str()))
+        .collect();
+    let leaked: &'static [&'static str] = Box::leak(leaked.into_boxed_slice());
+    let attributes = tauri_build::Attributes::new()
+        .app_manifest(tauri_build::AppManifest::new().commands(leaked));
+    if let Err(error) = tauri_build::try_build(attributes) {
+        // Same shape as `tauri_build::build()`: message on stdout, then exit 1.
+        println!("{error:#}");
+        std::process::exit(1);
+    }
+}
+
+/// tauri-build writes `permissions/autogenerated/<command>.toml` for every manifest command
+/// and never deletes one, so a command removed from `lib.rs` would leave a permission a
+/// capability could still reference (and the build would pass). Delete only the stale files:
+/// tauri-build also emits `rerun-if-changed=permissions`, so regenerating everything would
+/// touch every mtime and re-run this script — and recompile the crate — on every cargo
+/// invocation. Anything else under `permissions/` is a hand-written grant the census cannot
+/// see, so it is refused — except OS/editor junk (`.DS_Store`, swap files), which tauri never
+/// loads and which is skipped (see `command_census::is_os_junk`).
+fn prune_permissions(commands: &[String]) {
+    let root = Path::new("permissions");
+    let Ok(entries) = std::fs::read_dir(root) else {
+        return;
+    };
+    for entry in entries {
+        let path = entry.expect("readable entry in permissions/").path();
+        if path.is_file() && command_census::is_os_junk(&file_name(&path)) {
+            // .DS_Store and friends: tauri never loads them, so they cannot grant anything.
+            continue;
+        }
+        if path.file_name().is_some_and(|n| n == "autogenerated") && path.is_dir() {
+            for file in std::fs::read_dir(&path).expect("readable permissions/autogenerated") {
+                let file = file.expect("readable entry").path();
+                let stem = file.file_stem().and_then(|s| s.to_str()).unwrap_or("");
+                let live = file.extension().is_some_and(|e| e == "toml")
+                    && commands.iter().any(|c| c == stem);
+                if !live {
+                    std::fs::remove_file(&file)
+                        .unwrap_or_else(|e| panic!("cannot delete stale {}: {e}", file.display()));
+                }
+            }
+        } else {
+            fail(
+                "hand-written permission",
+                &[format!(
+                    "{} is not generated by build.rs; hand-written permissions are not allowed \
+                     (every grant is a bare allow-* string in a capability file)",
+                    path.display()
+                )],
+                "permissions/ holds only build.rs's autogenerated/ directory. Delete the entry; \
+                 an app command is granted by listing allow-<command> in a capability file.",
+            );
+        }
+    }
+}
+
+/// Every capability tauri will load, read the way the census reads it — or the build stops.
+/// tauri-build loads `capabilities/**/*.{json,toml,json5}`; the census reads only top-level
+/// `*.json`, so anything else tauri could load is refused rather than granted unchecked.
+fn read_capabilities() -> Vec<command_census::CapabilityFile> {
+    let mut files = Vec::new();
+    let mut stray = Vec::new();
+    let mut invalid = Vec::new();
+    for entry in std::fs::read_dir("capabilities").expect("capabilities/ must exist") {
+        let path = entry.expect("readable entry in capabilities/").path();
+        let name = file_name(&path);
+        let is_file = path.is_file();
+        if is_file && command_census::is_os_junk(&name) {
+            continue;
+        }
+        if let Some(problem) = command_census::stray_capability_entry(&name, is_file) {
+            stray.push(problem);
+            continue;
+        }
+        let json = std::fs::read_to_string(&path).unwrap_or_else(|e| panic!("{name}: {e}"));
+        match command_census::capability_file(&name, &json) {
+            Ok(file) => files.push(file),
+            Err(problem) => invalid.push(problem),
+        }
+    }
+    stray.sort();
+    if !stray.is_empty() {
+        fail("stray entry in capabilities/", &stray, LAYOUT_HINT);
+    }
+    invalid.sort();
+    if !invalid.is_empty() {
+        fail("invalid capability file", &invalid, LAYOUT_HINT);
+    }
+    files.sort_by(|a, b| a.name.cmp(&b.name));
+    files
+}
+
+/// tauri also takes capabilities inline from `app.security.capabilities` in any of its config
+/// files, or from the `TAURI_CONFIG` JSON that tauri-build merges over them. The census cannot
+/// see those, so they are refused; so is a config in a format it cannot read (JSON5, TOML).
+fn check_tauri_config() {
+    let mut problems = Vec::new();
+    for entry in std::fs::read_dir(".").expect("readable src-tauri/") {
+        let path = entry.expect("readable entry in src-tauri/").path();
+        let name = file_name(&path);
+        match command_census::tauri_config_file(&name) {
+            None => {}
+            Some(false) => problems.push(format!(
+                "{name}: the census reads JSON tauri configs only; a JSON5/TOML config could \
+                 declare capabilities it cannot see"
+            )),
+            Some(true) => {
+                let json =
+                    std::fs::read_to_string(&path).unwrap_or_else(|e| panic!("{name}: {e}"));
+                problems.extend(command_census::tauri_config_problem(&name, &json));
+            }
+        }
+    }
+    if let Ok(json) = std::env::var("TAURI_CONFIG") {
+        problems.extend(command_census::tauri_config_problem("TAURI_CONFIG", &json));
+    }
+    problems.sort();
+    if !problems.is_empty() {
+        fail("capabilities declared outside capabilities/", &problems, LAYOUT_HINT);
+    }
 }

app/src-tauri/capabilities/file-viewer.json

@@ -0,0 +1,16 @@
+{
+  "identifier": "file-viewer",
+  "description": "The terminal file viewer windows (`file-viewer-<n>`, opened by `open_file_viewer` on the app's own `viewer.html`). Same rules as `default.json`, including the layout checks: this file itself must stay a top-level `capabilities/*.json` with no `webviews` or `remote` key, or `build.rs` refuses the build rather than grant something the census cannot see. The five bare `allow-viewer-*` grants are the only app commands a viewer window can invoke: `build.rs` declares the AppManifest that makes tauri enforce that, and refuses any other bare grant in this file. The label gate inside `commands/file_viewer_commands.rs` is still what stops window A acting on window B's registry entry, because the ACL only decides which window may call. The rest of this file is the plugin-command surface a compromised viewer webview could reach, and it is the smallest one that lets the window work. `core:event:allow-listen`/`allow-unlisten` are for `file-viewer-goto` (Rust → this window; the viewer subscribes through `getCurrentWindow().listen`, because a bare `listen()` in *any* window receives an `emit_to`). `core:window:allow-destroy` is not optional: `getCurrentWindow().onCloseRequested` in @tauri-apps/api 2.11 makes Rust `prevent_close()` whenever a JS listener exists and then calls `destroy()` itself, so without this grant the window's X button does nothing once the unsaved-changes guard is installed. `allow-close` is deliberately absent — nothing calls it, and `destroy` is the only exit. No `set-title`/`set-focus`/`unminimize`: those are done from Rust when a second click targets an already-open file. `core:webview:allow-internal-toggle-devtools` is the same dev-only convenience `default.json` carries.",
+  "windows": ["file-viewer-*"],
+  "permissions": [
+    "core:event:allow-listen",
+    "core:event:allow-unlisten",
+    "core:window:allow-destroy",
+    "core:webview:allow-internal-toggle-devtools",
+    "allow-viewer-get-state",
+    "allow-viewer-choose-file",
+    "allow-viewer-read-file",
+    "allow-viewer-poll-file",
+    "allow-viewer-write-file"
+  ]
+}

app/src-tauri/src/browser_view/commands.rs

@@ -15,6 +15,12 @@ use crate::AppState;
 /// non-`Running` status carrying an explanation rather than an error, so the
 /// pane always has something specific to say. This is host-side only — no
 /// container recreation is involved either way.
+///
+/// Either way the choice is persisted, so it survives an app restart. This is
+/// the only caller allowed to write `false`: every other path to
+/// [`BrowserViewManager::stop`](crate::browser_view::BrowserViewManager::stop)
+/// is a teardown rather than the user changing their mind. Enabling persists
+/// inside `start`, which is the single funnel for it.
 #[tauri::command]
 pub async fn set_browser_view_enabled(
     project_id: String,
@@ -23,9 +29,32 @@ pub async fn set_browser_view_enabled(
     state: State<'_, AppState>,
 ) -> Result<BrowserViewStatus, String> {
     if !enabled {
+        // Persist first, then tear down: the supervisor's own teardown emit
+        // reads this flag back out of the store, and reading it mid-stop would
+        // announce a view that is going away as still enabled.
+        //
+        // But the write's outcome is a *value*, not a branch. A `?` here meant
+        // that a store with no such project record returned early and
+        // `manager().stop()` never ran, leaving the supervisor, the proxy and
+        // the host port up for a project that, as far as the user is concerned,
+        // just had its view switched off. That state is not hypothetical while
+        // a session is live — the supervisor's own `store.get()` check in
+        // [`crate::browser_view`] exists because a record can go away
+        // underneath it — and before the flag was persisted at all, turning the
+        // view off always tore the session down.
+        let persisted = state
+            .projects_store
+            .set_browser_view_enabled(&project_id, false);
         // Awaits the supervisor, so the host port is released before we return.
-        manager().stop(&project_id).await;
-        return Ok(manager().status(&project_id).await);
+        //
+        // A failed write is still reported rather than logged and swallowed.
+        // The resources are gone either way by this point, so surfacing it
+        // costs nothing that matters, and the failure it describes is one the
+        // user needs: the stored flag still says *enabled*, so the view comes
+        // back by itself on the next launch. Returning `Ok` would be a claim
+        // about persistence that isn't true.
+        tear_down_then_report(persisted, manager().stop(&project_id)).await?;
+        return Ok(manager().status(&project_id, false).await);
     }
 
     let container_id = running_container(&state, &project_id, "opening the browser view").await?;
@@ -40,10 +69,31 @@ pub async fn set_browser_view_enabled(
         .await
 }
 
-/// Current status. Cheap: reads in-process state only, never the container.
+/// Await `teardown`, then report `persisted`.
+///
+/// Trivial on purpose, and split out for one reason: it is the whole rule the
+/// disable path of [`set_browser_view_enabled`] has to obey — the teardown is
+/// unconditional, and a failed persist surfaces only after it has run — and as
+/// a free function that rule can be tested without a live `AppState`.
+async fn tear_down_then_report(
+    persisted: Result<(), String>,
+    teardown: impl std::future::Future<Output = ()>,
+) -> Result<(), String> {
+    teardown.await;
+    persisted
+}
+
+/// Current status. Cheap: the session map in this process plus the stored flag,
+/// never the container.
+///
+/// The two are independent on purpose — this is what the pane reads on mount,
+/// and after an app restart the honest answer is "enabled, nothing running".
 #[tauri::command]
-pub async fn get_browser_view_status(project_id: String) -> Result<BrowserViewStatus, String> {
-    Ok(manager().status(&project_id).await)
+pub async fn get_browser_view_status(
+    project_id: String,
+    state: State<'_, AppState>,
+) -> Result<BrowserViewStatus, String> {
+    Ok(manager().status(&project_id, enabled_for(&state, &project_id)).await)
 }
 
 /// Probe the container for Playwright without starting anything.
@@ -110,7 +160,9 @@ pub async fn open_browser_view_popout(
     app_handle: AppHandle,
     state: State<'_, AppState>,
 ) -> Result<(), String> {
-    let status = manager().status(&project_id).await;
+    let status = manager()
+        .status(&project_id, enabled_for(&state, &project_id))
+        .await;
     let (BrowserViewState::Running, Some(url)) = (status.state, status.url.as_deref()) else {
         return Err(
             "The browser view isn't running. Start it before opening it in its own window."
@@ -209,7 +261,9 @@ pub async fn open_page_in_container_browser(
     // the user to go and press Start in the Browser tab themselves — and from
     // the terminal's URL prompt, with no indication that was even needed.
     // Asking for a page *is* asking to watch it, so the viewer comes up too.
-    let status = manager().status(&project_id).await;
+    let status = manager()
+        .status(&project_id, enabled_for(&state, &project_id))
+        .await;
     if status.state != BrowserViewState::Running {
         crate::commands::project_commands::emit_progress(
             &app_handle,
@@ -229,7 +283,9 @@ pub async fn open_page_in_container_browser(
     // From the terminal there is no pane on screen to fill, so the page needs a
     // window of its own or it lands somewhere the user isn't looking.
     if show_window {
-        let status = manager().status(&project_id).await;
+        let status = manager()
+            .status(&project_id, enabled_for(&state, &project_id))
+            .await;
         if let Some(url) = status.url.as_deref() {
             let name = state
                 .projects_store
@@ -311,6 +367,20 @@ pub async fn get_browser_view_match_window(project_id: String) -> Result<bool, S
     Ok(popout::match_window(&project_id))
 }
 
+/// The project's stored browser-view opt-in.
+///
+/// The manager holds no copy of this — see
+/// [`BrowserViewManager`](crate::browser_view::BrowserViewManager) — so every
+/// status call reads it here, the way `get_auth_bridge_status` does. A project
+/// that has gone away reads as off, which is the only answer that can be given
+/// about a record that no longer exists.
+fn enabled_for(state: &State<'_, AppState>, project_id: &str) -> bool {
+    state
+        .projects_store
+        .get(project_id)
+        .is_some_and(|p| p.browser_view_enabled)
+}
+
 /// The project's container, or a sentence saying why there isn't one.
 ///
 /// Every command here needs a *running* container, and every one of them used
@@ -344,3 +414,43 @@ async fn running_container(
     }
     Ok(container_id)
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::sync::atomic::{AtomicBool, Ordering};
+
+    /// The regression: turning the view off must not leave the supervisor, the
+    /// proxy and the host port running just because the project record could
+    /// not be written — which is exactly what a missing record did.
+    #[tokio::test]
+    async fn a_failed_persist_does_not_skip_the_teardown() {
+        let torn_down = AtomicBool::new(false);
+        let result = tear_down_then_report(Err("Project x not found".to_string()), async {
+            torn_down.store(true, Ordering::SeqCst);
+        })
+        .await;
+
+        assert!(
+            torn_down.load(Ordering::SeqCst),
+            "the session must be torn down even when the store write failed"
+        );
+        assert_eq!(
+            result.err().as_deref(),
+            Some("Project x not found"),
+            "and the write failure must still reach the caller, not be swallowed"
+        );
+    }
+
+    #[tokio::test]
+    async fn a_successful_persist_reports_success_after_the_teardown() {
+        let torn_down = AtomicBool::new(false);
+        let result = tear_down_then_report(Ok(()), async {
+            torn_down.store(true, Ordering::SeqCst);
+        })
+        .await;
+
+        assert!(torn_down.load(Ordering::SeqCst));
+        assert!(result.is_ok());
+    }
+}

app/src-tauri/src/browser_view/mod.rs

@@ -34,14 +34,22 @@
 //!
 //! ## Lifecycle
 //!
-//! Off by default and per-project opt-in, exactly like `auth_bridge_enabled`.
+//! Off by default and per-project opt-in. The opt-in itself is
+//! [`Project::browser_view_enabled`](crate::models::Project), persisted like
+//! `auth_bridge_enabled` and read from the store on demand rather than cached
+//! here — so the pane comes back the way it was left. What does *not* persist
+//! is the session: nothing starts a viewer on app start, so a project left
+//! enabled reports `enabled: true` with a state of `Off` until the pane asks
+//! for one. That is deliberate, and the reason the flag and the session are
+//! separate ideas — see [`BrowserViewManager::status`].
+//!
 //! One supervisor task per session owns the proxy and the viewer process, and it
 //! is the only thing that tears them down, so every way a session can end funnels
 //! through one code path:
 //!
 //! | Trigger | Path |
 //! |---|---|
-//! | Turned off in the UI | `set_browser_view_enabled(false)` → [`BrowserViewManager::stop`] |
+//! | Turned off in the UI | `set_browser_view_enabled(false)` → persist `false`, then [`BrowserViewManager::stop`] |
 //! | Container stopped, by the UI or otherwise | supervisor's `is_container_running` check |
 //! | Project deleted | supervisor's `store.get()` check |
 //! | Container rebuilt | old container stops → supervisor exits; the new one is not auto-started |
@@ -59,7 +67,10 @@
 //! orphan is reachable on container loopback only: the host-side port dies with
 //! the app, and [`crate::auth_bridge::RESERVED_CONTAINER_PORTS`] is a constant
 //! precisely so the bridge will not mirror an orphan the next time the app
-//! starts. The next [`BrowserViewManager::start`] reclaims it.
+//! starts. The next [`BrowserViewManager::start`] reclaims it — and since the
+//! opt-in is now durable, the restarted app says `enabled` with nothing running,
+//! which is exactly the state that invites the user to press the button that
+//! reclaims it. Nothing reclaims it on its own, because nothing auto-starts.
 
 pub mod commands;
 pub mod detect;
@@ -134,7 +145,10 @@ pub enum BrowserViewState {
 
 #[derive(Debug, Clone, Serialize)]
 pub struct BrowserViewStatus {
-    /// The per-project opt-in. Off by default.
+    /// The per-project opt-in, read from the persisted project record. Off by
+    /// default, and true without a `Running` state whenever the view is turned
+    /// on but has nothing up — a stopped container, or an app that has just
+    /// restarted and does not auto-start viewers.
     pub enabled: bool,
     pub state: BrowserViewState,
     /// Fully-formed, token-bearing URL for the pane's iframe. Loopback only.
@@ -201,17 +215,20 @@ struct Session {
 
 type SessionMap = Arc<Mutex<HashMap<String, Session>>>;
 
+/// Live sessions, and nothing else.
+///
+/// The per-project opt-in deliberately is **not** a field here. It lives on
+/// the project record as
+/// [`browser_view_enabled`](crate::models::Project::browser_view_enabled) and
+/// is read from [`ProjectsStore`] at each use, exactly as
+/// [`crate::auth_bridge::AuthBridgeManager`] treats `auth_bridge_enabled`:
+/// one copy, durable across a restart, and impossible to get out of step with
+/// what the Config tab shows. A cached copy here was the previous design and
+/// its only observable behaviour was forgetting the user's choice on every
+/// app start.
 #[derive(Default)]
 pub struct BrowserViewManager {
     sessions: SessionMap,
-    /// The per-project opt-in.
-    ///
-    /// NOTE: in memory only, so it does not survive an app restart. The durable
-    /// home for this is a `browser_view_enabled: bool` field on
-    /// `models::Project` (see the report) — `models/project.rs` is out of scope
-    /// for this change, so the flag lives here and the wiring is otherwise
-    /// identical to `auth_bridge_enabled`.
-    enabled: Mutex<std::collections::HashSet<String>>,
     next_epoch: AtomicU64,
 }
 
@@ -226,22 +243,15 @@ pub fn manager() -> &'static Arc<BrowserViewManager> {
 }
 
 impl BrowserViewManager {
-    pub async fn is_enabled(&self, project_id: &str) -> bool {
-        self.enabled.lock().await.contains(project_id)
-    }
-
-    async fn set_enabled(&self, project_id: &str, enabled: bool) {
-        let mut set = self.enabled.lock().await;
-        if enabled {
-            set.insert(project_id.to_string());
-        } else {
-            set.remove(project_id);
-        }
-    }
-
     /// Current status without touching the container.
-    pub async fn status(&self, project_id: &str) -> BrowserViewStatus {
-        let enabled = self.is_enabled(project_id).await;
+    ///
+    /// `enabled` is passed in rather than looked up, the way
+    /// [`crate::auth_bridge::AuthBridgeManager::status`] takes it: the flag is
+    /// the caller's to read from the store, and keeping it out of here is what
+    /// stops a second copy of it appearing. A project whose view is enabled but
+    /// whose container is stopped — or whose app has just restarted — reports
+    /// `enabled: true` with a state of `Off`, which is the honest answer.
+    pub async fn status(&self, project_id: &str, enabled: bool) -> BrowserViewStatus {
         match self.sessions.lock().await.get(project_id) {
             Some(session) => BrowserViewStatus {
                 enabled,
@@ -261,6 +271,14 @@ impl BrowserViewManager {
     ///
     /// Idempotent: a call while a live session exists returns that session's
     /// status untouched, so re-opening the tab does not restart the dashboard.
+    ///
+    /// This is the single funnel for turning the view **on**, so it is also
+    /// where the durable flag is written — both call sites (the toggle and
+    /// `open_page_in_container_browser`, which opens a page and then shows it)
+    /// mean "on", and neither can forget. The **off** direction is not
+    /// symmetric and must not be: [`Self::stop`] is reached by teardown paths
+    /// that are not the user changing their mind, so the command owns that
+    /// write. See [`Self::stop`].
     pub async fn start(
         &self,
         project_id: String,
@@ -268,7 +286,7 @@ impl BrowserViewManager {
         app: AppHandle,
         store: Arc<ProjectsStore>,
     ) -> Result<BrowserViewStatus, String> {
-        self.set_enabled(&project_id, true).await;
+        store.set_browser_view_enabled(&project_id, true)?;
 
         // Bind the answer before acting on it: `status()` takes the same lock,
         // and this mutex is not reentrant.
@@ -279,7 +297,7 @@ impl BrowserViewManager {
             .get(&project_id)
             .is_some_and(|s| !s.supervisor.is_finished());
         if already_live {
-            return Ok(self.status(&project_id).await);
+            return Ok(self.status(&project_id, true).await);
         }
 
         let detection = detect::detect(&container_id).await?;
@@ -364,14 +382,21 @@ impl BrowserViewManager {
             },
         );
 
-        let status = self.status(&project_id).await;
+        let status = self.status(&project_id, true).await;
         emit(&app, &project_id, &status);
         Ok(status)
     }
 
     /// Stop one project's view and wait until its host port has been released.
+    ///
+    /// Tears the *session* down and deliberately leaves the durable flag alone.
+    /// Most callers are not the user turning the feature off — a migration
+    /// removes the container out from under a running view
+    /// (`migration_commands`), and the container can stop for any other reason
+    /// — and persisting `false` for those would quietly opt the project out of
+    /// a feature it never asked to lose. `set_browser_view_enabled(false)` is
+    /// the one caller that means it, and it writes the flag itself first.
     pub async fn stop(&self, project_id: &str) {
-        self.set_enabled(project_id, false).await;
         // Remove under the lock, then release it before awaiting: the
         // supervisor takes the same lock to deregister itself on exit.
         let session = self.sessions.lock().await.remove(project_id);
@@ -483,7 +508,12 @@ async fn supervise(
     // longer exists. The session owns it, and this is where the session ends.
     let _ = popout::close(&app, &project_id);
 
-    let enabled = manager().is_enabled(&project_id).await;
+    // Straight from the store, like the auth bridge's own teardown emit: the
+    // session is over, but the project may well still be opted in — a stopped
+    // container is not a changed mind, and the pane has to show the difference.
+    let enabled = store
+        .get(&project_id)
+        .is_some_and(|p| p.browser_view_enabled);
     emit(&app, &project_id, &BrowserViewStatus::off(enabled));
 }
 
@@ -915,6 +945,25 @@ mod tests {
         assert!(s.url.is_none());
     }
 
+    #[tokio::test]
+    async fn the_opt_in_and_the_live_session_are_separate_answers() {
+        let manager = BrowserViewManager::default();
+
+        // Exactly what the pane reads on mount after an app restart of a
+        // project that was left enabled: the durable flag says on, and nothing
+        // auto-starts, so the state is honestly `Off`. The old in-memory flag
+        // could not express this — it came back `false` and the pane silently
+        // showed the feature as never having been turned on.
+        let status = manager.status("p1", true).await;
+        assert!(status.enabled);
+        assert_eq!(status.state, BrowserViewState::Off);
+        assert!(status.url.is_none());
+
+        // The flag belongs to the caller, read from the store. The manager
+        // keeps no copy, so it has nothing to contradict it with.
+        assert!(!manager.status("p1", false).await.enabled);
+    }
+
     #[test]
     fn an_unavailable_status_keeps_the_detail_the_user_needs() {
         let mut d = PlaywrightDetection::default();

app/src-tauri/src/command_census.rs

@@ -0,0 +1,581 @@
+//! The command census shared by `build.rs` and the `cargo test` suite.
+//!
+//! `build.rs` pulls this file in with `#[path = "src/command_census.rs"]` and `lib.rs` with
+//! `#[cfg(test)] mod command_census;`, so the parser that decides what the Tauri `AppManifest`
+//! declares is the parser the tests exercise, and the rules that decide whether the build
+//! passes have unit tests. Nothing here may reference the crate: only `std` and `serde_json`
+//! (a dependency of both the crate and the build script).
+//!
+//! Spec: `docs/superpowers/specs/2026-09-22-app-manifest-lockdown-design.md` §3.2.
+
+use std::collections::{BTreeMap, BTreeSet};
+
+/// The command names inside `generate_handler![ … ])` in `lib.rs`, in registration order,
+/// duplicates kept (the caller decides whether that is an error). `None` if the block is
+/// missing or unterminated.
+///
+/// Comma-split, not line-split: `// Docker` style comments are stripped from every line first
+/// (a whole-line comment strips to nothing; a trailing one leaves the code before it), and the
+/// *cleaned* text is then split on `,` so each grant is its own item regardless of how many
+/// share a line. A line-split version of this parser shipped first and used
+/// `rsplit("::").next()` once *per line*: two commands on one line (`a::x, b::y,`) collapsed to
+/// a single item, silently dropping `a::x` — a denied command at runtime with nothing flagging
+/// it. Comma-splitting fixes that because it no longer assumes one item per line.
+pub fn registered_commands(lib_rs: &str) -> Option<Vec<String>> {
+    let (_, rest) = lib_rs.split_once("generate_handler![")?;
+    let (inside, _) = rest.split_once("])")?;
+    let cleaned: String = inside
+        .lines()
+        // Strip a trailing `//` comment (and a whole-line one, which strips to "").
+        .map(|l| l.split("//").next().unwrap_or(""))
+        .collect::<Vec<_>>()
+        .join("\n");
+    Some(
+        cleaned
+            .split(',')
+            .map(str::trim)
+            .filter(|s| !s.is_empty())
+            .filter_map(|s| {
+                // `a::b::name` → `name`; a bare `name` (no `::`) is its own last segment.
+                s.rsplit("::").next().map(|n| n.trim().to_string())
+            })
+            .filter(|n| !n.is_empty())
+            .collect(),
+    )
+}
+
+/// `viewer_read_file` → `allow-viewer-read-file`. tauri-utils 2.9.0 (`acl/build.rs:290`)
+/// replaces only `_`; permission identifiers may not contain `_`, but the command name inside
+/// the generated permission stays snake_case.
+pub fn allow_permission(command: &str) -> String {
+    format!("allow-{}", command.replace('_', "-"))
+}
+
+/// The `windows` list of the one capability file that may grant `command`. A command that
+/// must be callable from both windows is a design change: make it here, visibly, rather than
+/// by widening a capability file.
+pub fn expected_windows(command: &str) -> &'static [&'static str] {
+    if command.starts_with("viewer_") {
+        &["file-viewer-*"]
+    } else {
+        &["main"]
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct CapabilityFile {
+    pub name: String,
+    pub windows: Vec<String>,
+    pub bare: Vec<String>,
+}
+
+/// One `capabilities/*.json`, reduced to what the census checks. Plugin and core grants
+/// (anything with a `:`) are not this module's business; the exact-set tests in `lib.rs` and
+/// `file_viewer/mod.rs` pin those.
+pub fn capability_file(name: &str, json: &str) -> Result<CapabilityFile, String> {
+    let value: serde_json::Value =
+        serde_json::from_str(json).map_err(|e| format!("{name}: not valid JSON: {e}"))?;
+    // `webviews` would extend the grants to webviews by label (the browser-view pop-out is
+    // meant to be in no capability), and `remote` would extend them to a remote origin. The
+    // census reasons about `windows` only, so either key is refused rather than half-checked.
+    for key in ["webviews", "remote"] {
+        if value.get(key).is_some() {
+            return Err(format!(
+                "{name}: `{key}` is not allowed; capabilities here are scoped by `windows` only"
+            ));
+        }
+    }
+    let windows = value["windows"]
+        .as_array()
+        .ok_or_else(|| format!("{name}: `windows` must be an array"))?
+        .iter()
+        .map(|w| {
+            w.as_str()
+                .map(str::to_string)
+                .ok_or_else(|| format!("{name}: `windows` entries must be strings"))
+        })
+        .collect::<Result<Vec<_>, _>>()?;
+    let mut bare = Vec::new();
+    for grant in value["permissions"]
+        .as_array()
+        .ok_or_else(|| format!("{name}: `permissions` must be an array"))?
+    {
+        let id = match grant {
+            serde_json::Value::String(s) => s.as_str(),
+            serde_json::Value::Object(o) => o
+                .get("identifier")
+                .and_then(|i| i.as_str())
+                .ok_or_else(|| format!("{name}: a scoped grant needs a string `identifier`"))?,
+            _ => return Err(format!("{name}: a grant is a string or an object")),
+        };
+        if !id.contains(':') {
+            bare.push(id.to_string());
+        }
+    }
+    Ok(CapabilityFile { name: name.to_string(), windows, bare })
+}
+
+/// Why an entry directly under `capabilities/` cannot be a capability the census reads, or
+/// `None` if it is one (a top-level `*.json` file). tauri-build loads `capabilities/**/*` with
+/// the extensions `json`, `toml` and (with a feature) `json5`, subdirectories included; the
+/// census reads only top-level JSON, so anything else tauri might load is refused rather than
+/// left for tauri to grant from unchecked. OS and editor junk, which tauri never loads, is the
+/// caller's to skip first (see [`is_os_junk`]).
+pub fn stray_capability_entry(name: &str, is_file: bool) -> Option<String> {
+    if !is_file {
+        return Some(format!(
+            "capabilities/{name} is not a regular file; tauri loads capabilities from \
+             subdirectories too, so every capability must be a top-level capabilities/*.json"
+        ));
+    }
+    if name.ends_with(".json") {
+        return None;
+    }
+    Some(format!(
+        "capabilities/{name} is not a .json file; tauri may load it (it reads .toml and .json5 \
+         too) but the census cannot check it, so every capability must be a top-level \
+         capabilities/*.json"
+    ))
+}
+
+/// Files the OS or an editor drops next to real ones (`.DS_Store`, `Thumbs.db`, `desktop.ini`,
+/// Vim swap files, `name~` backups). tauri-build loads only `json`/`toml`/`json5` from
+/// `capabilities/` and `permissions/`, so a junk name with one of those extensions (an Emacs
+/// `.#default.json` lock, a macOS `._default.json`) is *not* junk: tauri would try to load it,
+/// and the caller must refuse it.
+pub fn is_os_junk(name: &str) -> bool {
+    let loadable = [".json", ".json5", ".toml"].iter().any(|e| name.ends_with(e));
+    !loadable
+        && (matches!(name, ".DS_Store" | "Thumbs.db" | "desktop.ini")
+            || name.ends_with(".swp")
+            || name.ends_with(".swo")
+            || name.ends_with('~'))
+}
+
+/// Which files next to `Cargo.toml` tauri reads as its config: `tauri.conf.json[5]`,
+/// `Tauri.toml` and the per-platform `tauri.<platform>.conf.json[5]` / `Tauri.<platform>.toml`
+/// (tauri-utils `config/parse.rs`). `Some(true)` = JSON the census can read, `Some(false)` = a
+/// format it cannot (JSON5/TOML), `None` = not a tauri config file.
+pub fn tauri_config_file(name: &str) -> Option<bool> {
+    if name.starts_with("tauri.") && name.ends_with(".conf.json") {
+        Some(true)
+    } else if (name.starts_with("tauri.") && name.ends_with(".conf.json5"))
+        || (name.starts_with("Tauri.") && name.ends_with(".toml"))
+    {
+        Some(false)
+    } else {
+        None
+    }
+}
+
+/// A problem with a tauri config (a `tauri*.conf.json` file, or the `TAURI_CONFIG` JSON that
+/// tauri-build merges over it), or `None`. `app.security.capabilities` is refused whenever it
+/// is non-empty: an inline object is a capability the census never sees, and a list of
+/// identifiers switches every *other* capability file off, which the census also assumes is
+/// not happening.
+pub fn tauri_config_problem(name: &str, json: &str) -> Option<String> {
+    let value: serde_json::Value = match serde_json::from_str(json) {
+        Ok(v) => v,
+        Err(e) => return Some(format!("{name}: not valid JSON: {e}")),
+    };
+    match value.pointer("/app/security/capabilities") {
+        None | Some(serde_json::Value::Null) => None,
+        Some(serde_json::Value::Array(a)) if a.is_empty() => None,
+        Some(_) => Some(format!(
+            "{name}: app.security.capabilities is not allowed; every capability lives in a \
+             top-level capabilities/*.json file, where the census checks it"
+        )),
+    }
+}
+
+/// Everything that must hold between the handler list and the capability files. Returns every
+/// violation rather than the first, so a batch of forgotten grants is one build failure; an
+/// empty vector is a pass.
+pub fn check(commands: &[String], files: &[CapabilityFile]) -> Vec<String> {
+    let mut problems = Vec::new();
+    if commands.is_empty() {
+        problems.push(
+            "no commands were parsed out of generate_handler! — an empty AppManifest would \
+             silently leave every app command ungated"
+                .to_string(),
+        );
+        return problems;
+    }
+
+    let mut seen: BTreeSet<&str> = BTreeSet::new();
+    for c in commands {
+        if !c.bytes().all(|b| b.is_ascii_lowercase() || b.is_ascii_digit() || b == b'_') {
+            problems.push(format!("{c:?} is not a command name ([a-z0-9_]+)"));
+        }
+        if !seen.insert(c.as_str()) {
+            problems.push(format!("{c} is registered more than once"));
+        }
+    }
+
+    let known: BTreeMap<String, &str> =
+        seen.iter().map(|c| (allow_permission(c), *c)).collect();
+    for f in files {
+        let windows: Vec<&str> = f.windows.iter().map(String::as_str).collect();
+        for id in &f.bare {
+            match known.get(id) {
+                Some(command) => {
+                    let want = expected_windows(command);
+                    if windows.as_slice() != want {
+                        problems.push(format!(
+                            "{}: {id} must be granted in the capability file whose windows are \
+                             {want:?}, not {windows:?}",
+                            f.name
+                        ));
+                    }
+                }
+                None if id.starts_with("deny-") => problems.push(format!(
+                    "{}: {id}: deny-* is global in tauri 2.11 — it would deny the command for \
+                     every window, not just this one; use allow-lists only",
+                    f.name
+                )),
+                None if id.starts_with("allow-") => problems.push(format!(
+                    "{}: {id} names no registered command (the identifier is allow-<command> \
+                     with every `_` replaced by `-`)",
+                    f.name
+                )),
+                None => problems.push(format!(
+                    "{}: {id}: only allow-<command> app grants are permitted as bare identifiers",
+                    f.name
+                )),
+            }
+        }
+    }
+
+    for c in &seen {
+        let id = allow_permission(c);
+        let holders: Vec<&str> = files
+            .iter()
+            .filter(|f| f.bare.iter().any(|b| b == &id))
+            .map(|f| f.name.as_str())
+            .collect();
+        match holders.len() {
+            0 => problems.push(format!(
+                "{c} is registered but no capability file grants {id}; add it to the file \
+                 whose windows are {:?}",
+                expected_windows(c)
+            )),
+            1 => {}
+            _ => problems.push(format!(
+                "{id} is granted in more than one capability file: {holders:?}"
+            )),
+        }
+    }
+    problems
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn cmds(names: &[&str]) -> Vec<String> {
+        names.iter().map(|n| n.to_string()).collect()
+    }
+
+    fn file(name: &str, windows: &[&str], bare: &[&str]) -> CapabilityFile {
+        CapabilityFile {
+            name: name.to_string(),
+            windows: windows.iter().map(|w| w.to_string()).collect(),
+            bare: bare.iter().map(|b| b.to_string()).collect(),
+        }
+    }
+
+    /// The two files as they must look after the lockdown, for a three-command app.
+    fn good_files() -> Vec<CapabilityFile> {
+        vec![
+            file("default.json", &["main"], &["allow-check-docker", "allow-open-file-viewer"]),
+            file("file-viewer.json", &["file-viewer-*"], &["allow-viewer-read-file"]),
+        ]
+    }
+
+    const THREE: &[&str] = &["check_docker", "open_file_viewer", "viewer_read_file"];
+
+    #[test]
+    fn the_parser_reads_the_handler_list_in_order_and_ignores_comments() {
+        let lib_rs = r#"
+            .invoke_handler(tauri::generate_handler![
+                // Docker
+                commands::docker_commands::check_docker,
+                commands::docker_commands::build_image, // trailing comment is not a command
+                url_open::open_url_external,
+
+                // Viewer
+                commands::file_viewer_commands::viewer_read_file
+            ])
+            .run(tauri::generate_context!())
+        "#;
+        assert_eq!(
+            registered_commands(lib_rs).unwrap(),
+            cmds(&["check_docker", "build_image", "open_url_external", "viewer_read_file"])
+        );
+    }
+
+    #[test]
+    fn the_parser_keeps_duplicates_so_the_caller_can_report_them() {
+        let lib_rs = "generate_handler![\n a::x,\n b::x,\n])";
+        assert_eq!(registered_commands(lib_rs).unwrap(), cmds(&["x", "x"]));
+    }
+
+    #[test]
+    fn the_parser_returns_none_without_a_handler_block() {
+        assert_eq!(registered_commands("fn main() {}"), None);
+        assert_eq!(registered_commands("generate_handler![ a::b, "), None, "unterminated");
+    }
+
+    /// The bug this regression-tests: a line-split parser applies `rsplit("::").next()` once
+    /// per *line*, so two commands sharing a line collapse into one item and the first is
+    /// silently dropped. Comma-splitting must keep both regardless of layout.
+    #[test]
+    fn two_commands_on_one_line_are_both_kept() {
+        let lib_rs = "generate_handler![\n a::x, b::y,\n])";
+        assert_eq!(registered_commands(lib_rs).unwrap(), cmds(&["x", "y"]));
+    }
+
+    /// Mirrors the real `lib.rs` handler list's shape: `// Section` comments between groups,
+    /// and command paths one (`open_url_external`), two (`url_open::open_url_external`) and
+    /// three (`commands::docker_commands::check_docker`) segments deep, all ending in a comma
+    /// except the last entry before `])`.
+    #[test]
+    fn a_fixture_shaped_like_the_real_handler_list_parses_every_command() {
+        let lib_rs = r#"
+            .invoke_handler(tauri::generate_handler![
+                // Docker
+                commands::docker_commands::check_docker,
+                commands::docker_commands::build_image,
+                // Opening a link in the host browser
+                url_open::open_url_external,
+                // Bare, module-less command
+                open_help,
+                // Terminal file viewer
+                commands::file_viewer_commands::viewer_read_file
+            ])
+            .run(tauri::generate_context!())
+        "#;
+        assert_eq!(
+            registered_commands(lib_rs).unwrap(),
+            cmds(&[
+                "check_docker",
+                "build_image",
+                "open_url_external",
+                "open_help",
+                "viewer_read_file",
+            ])
+        );
+    }
+
+    #[test]
+    fn permission_identifiers_replace_only_underscores() {
+        assert_eq!(allow_permission("check_docker"), "allow-check-docker");
+        assert_eq!(allow_permission("viewer_read_file"), "allow-viewer-read-file");
+        assert_eq!(allow_permission("aws_sso_refresh"), "allow-aws-sso-refresh");
+    }
+
+    #[test]
+    fn viewer_commands_belong_to_the_viewer_windows_and_nothing_else_does() {
+        assert_eq!(expected_windows("viewer_read_file"), ["file-viewer-*"]);
+        assert_eq!(expected_windows("open_file_viewer"), ["main"]);
+        assert_eq!(expected_windows("check_docker"), ["main"]);
+    }
+
+    #[test]
+    fn a_capability_file_yields_its_windows_and_bare_grants_only() {
+        let json = r#"{
+            "identifier": "default",
+            "description": "x",
+            "windows": ["main"],
+            "permissions": [
+                "core:event:allow-listen",
+                { "identifier": "fs:allow-read", "allow": [{ "path": "$APPDATA/*" }] },
+                "allow-check-docker",
+                { "identifier": "allow-list-projects" }
+            ]
+        }"#;
+        let parsed = capability_file("default.json", json).unwrap();
+        assert_eq!(parsed.name, "default.json");
+        assert_eq!(parsed.windows, vec!["main"]);
+        assert_eq!(parsed.bare, vec!["allow-check-docker", "allow-list-projects"]);
+    }
+
+    #[test]
+    fn a_capability_file_without_windows_or_permissions_is_an_error() {
+        assert!(capability_file("x.json", r#"{"permissions": []}"#).unwrap_err().contains("windows"));
+        assert!(capability_file("x.json", r#"{"windows": ["main"]}"#).unwrap_err().contains("permissions"));
+        assert!(capability_file("x.json", "not json").unwrap_err().contains("x.json"));
+    }
+
+    #[test]
+    fn webviews_and_remote_keys_are_refused() {
+        let with = |extra: &str| {
+            format!(r#"{{"windows": ["main"], {extra}, "permissions": ["allow-check-docker"]}}"#)
+        };
+        let err = capability_file("d.json", &with(r#""webviews": ["browser-view-*"]"#)).unwrap_err();
+        assert!(err.contains("d.json") && err.contains("`webviews`"), "{err}");
+        let err = capability_file("d.json", &with(r#""remote": {"urls": ["https://*"]}"#)).unwrap_err();
+        assert!(err.contains("`remote`"), "{err}");
+        // Present-but-empty is still refused: the key itself is the widening surface.
+        assert!(capability_file("d.json", &with(r#""webviews": []"#)).is_err());
+    }
+
+    #[test]
+    fn only_top_level_json_files_are_capabilities() {
+        assert_eq!(stray_capability_entry("default.json", true), None);
+        for name in ["extra.toml", "extra.json5", "notes.txt", ".DS_Store"] {
+            let err = stray_capability_entry(name, true).expect(name);
+            assert!(err.contains(name) && err.contains("not a .json file"), "{err}");
+        }
+        let err = stray_capability_entry("sub", false).unwrap();
+        assert!(err.contains("capabilities/sub") && err.contains("not a regular file"), "{err}");
+        // A directory named like a capability is still a directory.
+        assert!(stray_capability_entry("x.json", false).is_some());
+    }
+
+    #[test]
+    fn os_junk_is_recognised_but_never_something_tauri_would_load() {
+        for junk in [".DS_Store", "Thumbs.db", "desktop.ini", ".default.json.swp", ".x.swo", "default.json~"] {
+            assert!(is_os_junk(junk), "{junk}");
+        }
+        for real in ["default.json", "x.toml", "x.json5", ".#default.json", "._default.json", "notes.txt", "extra"] {
+            assert!(!is_os_junk(real), "{real}");
+        }
+    }
+
+    #[test]
+    fn tauri_config_files_are_found_by_name_and_format() {
+        assert_eq!(tauri_config_file("tauri.conf.json"), Some(true));
+        assert_eq!(tauri_config_file("tauri.linux.conf.json"), Some(true));
+        assert_eq!(tauri_config_file("tauri.conf.json5"), Some(false));
+        assert_eq!(tauri_config_file("tauri.windows.conf.json5"), Some(false));
+        assert_eq!(tauri_config_file("Tauri.toml"), Some(false));
+        assert_eq!(tauri_config_file("Tauri.macos.toml"), Some(false));
+        assert_eq!(tauri_config_file("Cargo.toml"), None);
+        assert_eq!(tauri_config_file("build.rs"), None);
+    }
+
+    #[test]
+    fn inline_capabilities_in_the_tauri_config_are_refused() {
+        let ok = r#"{"app": {"security": {"csp": "default-src 'self'"}}}"#;
+        assert_eq!(tauri_config_problem("tauri.conf.json", ok), None);
+        assert_eq!(tauri_config_problem("t", r#"{"app": {"security": {"capabilities": []}}}"#), None);
+        assert_eq!(tauri_config_problem("t", r#"{"build": {"beforeBuildCommand": ""}}"#), None);
+        let inline = r#"{"app": {"security": {"capabilities": [
+            {"identifier": "x", "windows": ["file-viewer-*"], "permissions": ["allow-read-container-file"]}
+        ]}}}"#;
+        let err = tauri_config_problem("tauri.conf.json", inline).unwrap();
+        assert!(err.contains("tauri.conf.json") && err.contains("app.security.capabilities"), "{err}");
+        let by_name = r#"{"app": {"security": {"capabilities": ["default"]}}}"#;
+        assert!(tauri_config_problem("TAURI_CONFIG", by_name).unwrap().contains("TAURI_CONFIG"));
+        assert!(tauri_config_problem("t", "{").unwrap().contains("not valid JSON"));
+    }
+
+    #[test]
+    fn a_correct_census_has_no_problems() {
+        assert_eq!(check(&cmds(THREE), &good_files()), Vec::<String>::new());
+    }
+
+    #[test]
+    fn an_empty_command_list_is_refused_because_it_would_disable_the_acl() {
+        let problems = check(&[], &good_files());
+        assert_eq!(problems.len(), 1);
+        assert!(problems[0].contains("no commands"), "{problems:?}");
+    }
+
+    #[test]
+    fn a_command_without_a_grant_is_named_together_with_the_file_it_belongs_in() {
+        let files = vec![
+            file("default.json", &["main"], &["allow-check-docker"]),
+            file("file-viewer.json", &["file-viewer-*"], &["allow-viewer-read-file"]),
+        ];
+        let problems = check(&cmds(THREE), &files);
+        assert_eq!(problems.len(), 1, "{problems:?}");
+        assert!(problems[0].contains("open_file_viewer"));
+        assert!(problems[0].contains("allow-open-file-viewer"));
+        assert!(problems[0].contains("[\"main\"]"));
+    }
+
+    #[test]
+    fn a_grant_in_two_files_is_reported_once_naming_both() {
+        let files = vec![
+            file("default.json", &["main"], &["allow-check-docker", "allow-open-file-viewer"]),
+            file("extra.json", &["main"], &["allow-check-docker"]),
+            file("file-viewer.json", &["file-viewer-*"], &["allow-viewer-read-file"]),
+        ];
+        let problems = check(&cmds(THREE), &files);
+        assert_eq!(problems.len(), 1, "{problems:?}");
+        assert!(problems[0].contains("allow-check-docker"));
+        assert!(problems[0].contains("default.json") && problems[0].contains("extra.json"));
+    }
+
+    #[test]
+    fn a_grant_that_names_no_command_is_a_typo() {
+        let mut files = good_files();
+        files[0].bare.push("allow-check-dokcer".to_string());
+        let problems = check(&cmds(THREE), &files);
+        assert_eq!(problems.len(), 1, "{problems:?}");
+        assert!(problems[0].contains("default.json: allow-check-dokcer"));
+        assert!(problems[0].contains("no registered command"));
+    }
+
+    #[test]
+    fn deny_grants_are_refused_with_the_reason() {
+        let mut files = good_files();
+        files[1].bare.push("deny-check-docker".to_string());
+        let problems = check(&cmds(THREE), &files);
+        assert_eq!(problems.len(), 1, "{problems:?}");
+        assert!(problems[0].contains("file-viewer.json: deny-check-docker"));
+        assert!(problems[0].contains("global"));
+    }
+
+    #[test]
+    fn other_bare_identifiers_are_refused() {
+        let mut files = good_files();
+        files[0].bare.push("default".to_string());
+        let problems = check(&cmds(THREE), &files);
+        assert_eq!(problems.len(), 1, "{problems:?}");
+        assert!(problems[0].contains("default.json: default"));
+    }
+
+    #[test]
+    fn a_grant_in_the_wrong_file_is_refused_even_though_it_is_granted_exactly_once() {
+        let files = vec![
+            file("default.json", &["main"], &["allow-check-docker", "allow-open-file-viewer", "allow-viewer-read-file"]),
+            file("file-viewer.json", &["file-viewer-*"], &[]),
+        ];
+        let problems = check(&cmds(THREE), &files);
+        assert_eq!(problems.len(), 1, "{problems:?}");
+        assert!(problems[0].contains("allow-viewer-read-file"));
+        assert!(problems[0].contains("[\"file-viewer-*\"]"));
+    }
+
+    #[test]
+    fn a_widened_windows_list_is_the_wrong_file_too() {
+        let files = vec![
+            file("default.json", &["main", "file-viewer-*"], &["allow-check-docker", "allow-open-file-viewer"]),
+            file("file-viewer.json", &["file-viewer-*"], &["allow-viewer-read-file"]),
+        ];
+        let problems = check(&cmds(THREE), &files);
+        assert_eq!(problems.len(), 2, "{problems:?}");
+    }
+
+    #[test]
+    fn bad_names_and_duplicate_registrations_are_refused() {
+        let commands = cmds(&["check_docker", "Check-Docker", "check_docker", "open_file_viewer", "viewer_read_file"]);
+        let problems = check(&commands, &good_files());
+        assert!(problems.iter().any(|p| p.contains("\"Check-Docker\"") && p.contains("[a-z0-9_]+")), "{problems:?}");
+        assert!(problems.iter().any(|p| p.contains("check_docker is registered more than once")), "{problems:?}");
+    }
+
+    #[test]
+    fn every_problem_is_reported_in_one_pass() {
+        let files = vec![
+            file("default.json", &["main"], &["allow-check-docker", "allow-nope", "deny-check-docker"]),
+            file("file-viewer.json", &["file-viewer-*"], &[]),
+        ];
+        let problems = check(&cmds(THREE), &files);
+        // typo, deny, open_file_viewer missing, viewer_read_file missing
+        assert_eq!(problems.len(), 4, "{problems:?}");
+    }
+}

app/src-tauri/src/commands/docker_commands.rs

@@ -37,20 +37,3 @@ pub async fn get_container_info(
     docker::get_container_info(&project).await
 }
 
-#[tauri::command]
-pub async fn list_sibling_containers() -> Result<Vec<serde_json::Value>, String> {
-    let containers = docker::list_sibling_containers().await?;
-    let result: Vec<serde_json::Value> = containers
-        .into_iter()
-        .map(|c| {
-            serde_json::json!({
-                "id": c.id,
-                "names": c.names,
-                "image": c.image,
-                "state": c.state,
-                "status": c.status,
-            })
-        })
-        .collect();
-    Ok(result)
-}

app/src-tauri/src/commands/file_viewer_commands.rs

@@ -0,0 +1,365 @@
+//! IPC for the terminal file viewer. Every command here is gated on the calling
+//! window's label and reads its target from the registry — no path, no label, no
+//! project id crosses IPC from a viewer window. See spec §6.
+
+use base64::engine::general_purpose::STANDARD as BASE64;
+use base64::Engine as _;
+use serde::Serialize;
+use tauri::{AppHandle, Emitter, Manager, State};
+
+use crate::commands::file_commands::{
+    fetch_container_file, not_running_message, require_running, validate_container_write_path, MAX_READ_BYTES,
+};
+use crate::file_viewer::is_viewer_label;
+use crate::file_viewer::poll::{poll_file, ViewerPoll};
+use crate::file_viewer::registry::{
+    Choice, Location, Reservation, ViewerRegistry, ViewerTarget, ViewerTargetState,
+};
+use crate::file_viewer::resolve::{candidate_paths, probe_candidates};
+use crate::file_viewer::window::open_viewer_window;
+use crate::file_viewer::write::{sha256_hex, write_file, SavedFile, MAX_WRITE_BYTES};
+use crate::models::Project;
+use crate::AppState;
+
+pub const GOTO_EVENT: &str = "file-viewer-goto";
+
+#[derive(Clone, Debug, Serialize)]
+pub struct ViewerState {
+    pub project_id: String,
+    pub project_name: String,
+    pub raw_path: String,
+    pub state: ViewerTargetState,
+    pub initial: Location,
+}
+
+#[derive(Clone, Debug, Serialize)]
+pub struct ViewerFile {
+    pub contents_base64: String,
+    pub truncated: bool,
+    pub size: u64,
+    pub hash: String,
+    pub editable: bool,
+    pub readonly_reason: Option<String>,
+}
+
+fn require_main(window_label: &str) -> Result<(), String> {
+    if window_label == "main" {
+        Ok(())
+    } else {
+        Err("Only the main window can open files.".into())
+    }
+}
+
+fn require_viewer(window_label: &str) -> Result<String, String> {
+    if is_viewer_label(window_label) {
+        Ok(window_label.to_string())
+    } else {
+        Err("This command belongs to a file window.".into())
+    }
+}
+
+fn viewer_state_of(_label: &str, target: ViewerTarget) -> ViewerState {
+    ViewerState {
+        project_id: target.project_id,
+        project_name: target.project_name,
+        raw_path: target.raw_path,
+        state: target.state,
+        initial: target.initial,
+    }
+}
+
+fn window_title(raw_path: &str, project_name: &str) -> String {
+    let base = raw_path.trim_end_matches('/').rsplit('/').next().unwrap_or(raw_path);
+    format!("{} — {}", base, project_name)
+}
+
+/// Refuses a save payload before decoding it: base64 of at most
+/// [`MAX_WRITE_BYTES`] is at most `4 * ceil(MAX_WRITE_BYTES / 3)` characters.
+/// `write_file` enforces the cap on the decoded bytes too; this stops a
+/// compromised viewer from making the app allocate and decode an arbitrarily
+/// large string first.
+fn check_encoded_len(encoded_len: usize) -> Result<(), String> {
+    if encoded_len > MAX_WRITE_BYTES.div_ceil(3) * 4 {
+        return Err("Files over 1 MiB are read-only in the viewer.".into());
+    }
+    Ok(())
+}
+
+/// The caller's registry entry, or a sentence.
+fn own_target(
+    window: &tauri::Window,
+    registry: &ViewerRegistry,
+) -> Result<(String, ViewerTarget), String> {
+    let label = require_viewer(window.label())?;
+    let target = registry
+        .get(&label)
+        .ok_or_else(|| "This file window is no longer registered.".to_string())?;
+    Ok((label, target))
+}
+
+fn resolved_path(target: &ViewerTarget) -> Result<String, String> {
+    match &target.state {
+        ViewerTargetState::Resolved { container_path } => Ok(container_path.clone()),
+        _ => Err("Choose a file first.".into()),
+    }
+}
+
+/// The one place a viewer command looks up its project (P14).
+fn project_of(state: &AppState, project_id: &str) -> Result<Project, String> {
+    state
+        .projects_store
+        .get(project_id)
+        .ok_or_else(|| "This project no longer exists.".to_string())
+}
+
+/// `action` completes "Start the project before …", e.g. "saving this file".
+async fn running_container_of(project: &Project, action: &str) -> Result<String, String> {
+    let container_id = project
+        .container_id
+        .clone()
+        .ok_or_else(|| not_running_message(action, "files live in its container"))?;
+    require_running(&container_id, action).await?;
+    Ok(container_id)
+}
+
+/// The container of the project a viewer window belongs to, if it is running.
+async fn running_container_for(
+    state: &AppState,
+    target: &ViewerTarget,
+    action: &str,
+) -> Result<String, String> {
+    running_container_of(&project_of(state, &target.project_id)?, action).await
+}
+
+/// Raises an existing viewer window and moves it to `location`.
+fn focus_viewer(app: &AppHandle, label: &str, location: Location) {
+    if let Some(existing) = app.get_webview_window(label) {
+        let _ = existing.unminimize();
+        let _ = existing.set_focus();
+        let _ = app.emit_to(label, GOTO_EVENT, location);
+    }
+}
+
+// Nine parameters are fixed by the IPC contract (P10); four injected by Tauri.
+#[allow(clippy::too_many_arguments)]
+#[tauri::command]
+pub async fn open_file_viewer(
+    project_id: String,
+    path: String,
+    line: Option<u32>,
+    col: Option<u32>,
+    end_line: Option<u32>,
+    window: tauri::Window,
+    app: AppHandle,
+    registry: State<'_, ViewerRegistry>,
+    state: State<'_, AppState>,
+) -> Result<(), String> {
+    require_main(window.label())?;
+    let project = project_of(&state, &project_id)?;
+    let container_id = running_container_of(&project, "opening files").await?;
+
+    let mounts: Vec<String> = project.paths.iter().map(|p| p.mount_name.clone()).collect();
+    let candidates = candidate_paths(&path, &mounts)?;
+    let matches = probe_candidates(&container_id, &candidates).await?;
+    let initial = Location { line, col, end_line };
+
+    let target_state = match matches.len() {
+        0 => ViewerTargetState::NotFound { tried: candidates },
+        1 => ViewerTargetState::Resolved { container_path: matches[0].clone() },
+        _ => ViewerTargetState::Choose { candidates: matches },
+    };
+
+    let title = window_title(&path, &project.name);
+    let target = ViewerTarget {
+        project_id,
+        project_name: project.name.clone(),
+        raw_path: path,
+        state: target_state,
+        initial: initial.clone(),
+    };
+    // Dedupe, stale pruning and the cap are one registry call, so a second click
+    // while the first window is still being built finds it rather than reading
+    // its not-yet-existing window as stale.
+    let label = match registry.reserve(target, |l| app.get_webview_window(l).is_some())? {
+        Reservation::Reserved(label) => label,
+        // Still being built: it opens at its own location in a moment.
+        Reservation::Existing { built: false, .. } => return Ok(()),
+        Reservation::Existing { label, built: true } => {
+            focus_viewer(&app, &label, initial);
+            return Ok(());
+        }
+    };
+    if let Err(e) = open_viewer_window(&app, &label, &title) {
+        registry.remove(&label);
+        return Err(e);
+    }
+    registry.mark_built(&label);
+    Ok(())
+}
+
+#[tauri::command]
+pub async fn viewer_get_state(
+    window: tauri::Window,
+    registry: State<'_, ViewerRegistry>,
+) -> Result<ViewerState, String> {
+    let (label, target) = own_target(&window, &registry)?;
+    Ok(viewer_state_of(&label, target))
+}
+
+#[tauri::command]
+pub async fn viewer_choose_file(
+    index: usize,
+    window: tauri::Window,
+    registry: State<'_, ViewerRegistry>,
+) -> Result<ViewerState, String> {
+    let (label, target) = own_target(&window, &registry)?;
+    let chosen = match &target.state {
+        ViewerTargetState::Choose { candidates } => candidates
+            .get(index)
+            .cloned()
+            .ok_or_else(|| "That choice is no longer available.".to_string())?,
+        _ => return Err("This window is not choosing a file.".into()),
+    };
+    let app = window.app_handle();
+    match registry.choose(&label, chosen, |l| app.get_webview_window(l).is_some())? {
+        Choice::Resolved(updated) => Ok(viewer_state_of(&label, updated)),
+        // Another window already has this file. This window was only ever a
+        // chooser, so hand over to that one and close this one, as a second
+        // click on the same path would have. The error is what this window
+        // shows if the destroy fails.
+        Choice::AlreadyOpen { label: other, .. } => {
+            focus_viewer(app, &other, target.initial);
+            let _ = window.destroy();
+            Err("This file is already open in another window.".into())
+        }
+    }
+}
+
+#[tauri::command]
+pub async fn viewer_read_file(
+    max_bytes: u64,
+    window: tauri::Window,
+    registry: State<'_, ViewerRegistry>,
+    state: State<'_, AppState>,
+) -> Result<ViewerFile, String> {
+    let (_label, target) = own_target(&window, &registry)?;
+    let path = resolved_path(&target)?;
+    let container_id = running_container_for(&state, &target, "opening files").await?;
+    let cap = max_bytes.clamp(1, MAX_READ_BYTES);
+    let fetched = fetch_container_file(&container_id, &path, cap).await?;
+    let (editable, readonly_reason) = match validate_container_write_path("File", &path) {
+        Ok(()) => (true, None),
+        Err(reason) => (false, Some(reason)),
+    };
+    Ok(ViewerFile {
+        hash: sha256_hex(&fetched.bytes),
+        contents_base64: BASE64.encode(&fetched.bytes),
+        truncated: fetched.truncated,
+        size: fetched.size,
+        editable,
+        readonly_reason,
+    })
+}
+
+#[tauri::command]
+pub async fn viewer_poll_file(
+    window: tauri::Window,
+    registry: State<'_, ViewerRegistry>,
+    state: State<'_, AppState>,
+) -> Result<ViewerPoll, String> {
+    let (_label, target) = own_target(&window, &registry)?;
+    let path = resolved_path(&target)?;
+    let container_id = running_container_for(&state, &target, "checking this file for changes").await?;
+    poll_file(&container_id, &path).await
+}
+
+/// Errors from `write_file` pass through unchanged: the frontend matches the
+/// `write::CONFLICT_PREFIX`/`GONE_PREFIX` prefixes and `READ_ONLY_MESSAGE` (TS copies in
+/// `app/src/viewer/ipcMessages.ts`), and anything else (a full disk) is already a
+/// sentence it shows as is. Success is a `SavedFile`: the new base hash and the hash
+/// the disk held right after the swap.
+#[tauri::command]
+pub async fn viewer_write_file(
+    contents_base64: String,
+    base_hash: String,
+    window: tauri::Window,
+    registry: State<'_, ViewerRegistry>,
+    state: State<'_, AppState>,
+) -> Result<SavedFile, String> {
+    let (_label, target) = own_target(&window, &registry)?;
+    let path = resolved_path(&target)?;
+    validate_container_write_path("File", &path)?;
+    check_encoded_len(contents_base64.len())?;
+    let bytes = BASE64
+        .decode(contents_base64.as_bytes())
+        .map_err(|_| "The editor sent malformed content.".to_string())?;
+    let container_id = running_container_for(&state, &target, "saving this file").await?;
+    write_file(&container_id, &state.exec_manager, &path, &bytes, &base_hash).await
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn open_is_main_only_and_viewer_commands_are_viewer_only() {
+        assert!(require_main("main").is_ok());
+        assert!(require_main("file-viewer-1").is_err());
+        assert!(require_main("browser-view-x").is_err());
+        assert_eq!(require_viewer("file-viewer-7").unwrap(), "file-viewer-7");
+        assert!(require_viewer("main").is_err());
+        assert!(require_viewer("file-viewer-").is_err());
+    }
+
+    /// Both "no container" refusals a viewer command can give start with the prefix
+    /// the viewer reads as "Container not running" (`ipcMessages.ts`).
+    #[test]
+    fn not_running_refusals_carry_the_shared_prefix() {
+        use crate::commands::file_commands::NOT_RUNNING_PREFIX;
+        let m = not_running_message("checking this file for changes", "files live in its container");
+        assert_eq!(m, "Start the project before checking this file for changes — files live in its container.");
+        assert!(m.starts_with(NOT_RUNNING_PREFIX));
+    }
+
+    #[test]
+    fn a_saved_file_serialises_both_hashes() {
+        let json = serde_json::to_value(SavedFile { hash: "a".into(), disk_hash: "b".into() }).unwrap();
+        assert_eq!(json, serde_json::json!({ "hash": "a", "disk_hash": "b" }));
+    }
+
+    #[test]
+    fn the_title_is_basename_then_project() {
+        assert_eq!(window_title("app/src/lib/urlRelay.ts", "Triple-C"), "urlRelay.ts — Triple-C");
+        assert_eq!(window_title("/workspace/x/README.md", "x"), "README.md — x");
+        assert_eq!(window_title("Makefile", "p"), "Makefile — p");
+    }
+
+    #[test]
+    fn viewer_state_serialises_the_ipc_shape() {
+        let target = ViewerTarget {
+            project_id: "pid".into(),
+            project_name: "P".into(),
+            raw_path: "src/a.rs".into(),
+            state: ViewerTargetState::Resolved { container_path: "/workspace/p/src/a.rs".into() },
+            initial: Location { line: Some(3), col: Some(2), end_line: None },
+        };
+        let json = serde_json::to_value(viewer_state_of("file-viewer-1", target)).unwrap();
+        assert_eq!(json["project_id"], "pid");
+        assert_eq!(json["state"]["kind"], "resolved");
+        assert_eq!(json["state"]["container_path"], "/workspace/p/src/a.rs");
+        assert_eq!(json["initial"]["line"], 3);
+        assert!(json["initial"]["end_line"].is_null());
+    }
+
+    #[test]
+    fn the_encoded_length_is_capped_before_decoding() {
+        let at_cap = BASE64.encode(vec![0u8; MAX_WRITE_BYTES]);
+        assert!(check_encoded_len(at_cap.len()).is_ok());
+        // MAX + 1 and MAX + 2 bytes pad to the same length as MAX; `write_file`'s
+        // decoded check refuses those. The first size this bound itself refuses:
+        let over_cap = BASE64.encode(vec![0u8; MAX_WRITE_BYTES + 3]);
+        assert!(check_encoded_len(over_cap.len()).is_err());
+        assert!(check_encoded_len(at_cap.len() + 1).is_err());
+        assert!(check_encoded_len(0).is_ok());
+    }
+}

app/src-tauri/src/commands/mod.rs

@@ -3,13 +3,16 @@ pub mod auth_token_commands;
 pub mod aws_commands;
 pub mod docker_commands;
 pub mod file_commands;
+pub mod file_viewer_commands;
 pub mod gateway_commands;
 pub mod help_commands;
 pub mod inspect_commands;
 pub mod install_helper_commands;
 pub mod migration_commands;
+pub mod notes_commands;
 pub mod project_commands;
 pub mod settings_commands;
+pub mod settings_export_commands;
 pub mod stt_commands;
 pub mod terminal_commands;
 pub mod update_commands;

app/src-tauri/src/commands/notes_commands.rs

@@ -0,0 +1,33 @@
+use crate::models::Note;
+use crate::storage::notes_store;
+
+/// Every project's notes, oldest concept first: pinned notes, then most
+/// recently edited.
+///
+/// Sorted here rather than in the webview so the dock and the tab — two views
+/// of the same list — cannot drift into two different orders.
+#[tauri::command]
+pub async fn list_notes(project_id: String) -> Result<Vec<Note>, String> {
+    let mut notes = notes_store::load(&project_id)?;
+    notes.sort_by(|a, b| {
+        b.pinned
+            .cmp(&a.pinned)
+            .then_with(|| b.updated_at.cmp(&a.updated_at))
+    });
+    Ok(notes)
+}
+
+/// Insert or replace one note.
+///
+/// There is deliberately no whole-list setter. A bulk write is exactly the
+/// clobbering this store's per-project file exists to avoid, and every caller
+/// here is editing one note.
+#[tauri::command]
+pub async fn save_note(project_id: String, note: Note) -> Result<Note, String> {
+    notes_store::upsert(&project_id, note)
+}
+
+#[tauri::command]
+pub async fn delete_note(project_id: String, note_id: String) -> Result<(), String> {
+    notes_store::delete(&project_id, &note_id)
+}

app/src-tauri/src/commands/settings_commands.rs

@@ -10,12 +10,72 @@ pub async fn get_settings(state: State<'_, AppState>) -> Result<AppSettings, Str
     Ok(state.settings_store.get())
 }
 
+/// Everything `update_settings` refuses a save over, run against the store's
+/// *current* value and the incoming one.
+///
+/// Pulled out so a caller that does other, harder-to-undo work alongside a
+/// settings save — `settings_export_commands::apply_settings_import`
+/// restores three keychain secrets in the same command — can run this
+/// *first* and bail before touching anything, rather than discovering the
+/// rejection only when `update_settings` itself runs partway through.
+pub fn validate_settings_update(
+    before: &AppSettings,
+    incoming: &AppSettings,
+) -> Result<(), String> {
+    // The global half of the same rule the project half gets in
+    // `update_project`: a global custom env var is merged into every project's
+    // container environment, so an unchecked name here reaches all of them.
+    crate::models::validate_env_vars_update(
+        &before.global_custom_env_vars,
+        &incoming.global_custom_env_vars,
+    )?;
+
+    // The same for the two host paths this struct owns. `update_project`
+    // validated its per-project overrides and this side validated nothing,
+    // which left the wider hole of the two: `default_ssh_key_path` is the
+    // fallback for **every** project without an override
+    // (`container.rs`'s `create_container`), so `/` here read-only bind-mounts
+    // the whole host at `/tmp/.host-ssh` for all of them — and `entrypoint.sh`
+    // then does `cp -a /tmp/.host-ssh ~/.ssh`, recursively copying it into the
+    // home volume this release exists to bound.
+    //
+    // Grandfathered the same way project paths are: a value carried over
+    // unchanged still saves, so a store written before this check cannot lock
+    // the user out of their own settings.
+    crate::commands::project_commands::validate_mounted_host_path(
+        "SSH key path",
+        before.default_ssh_key_path.as_deref(),
+        incoming.default_ssh_key_path.as_deref(),
+    )?;
+    crate::commands::project_commands::validate_mounted_host_path(
+        "CA certificate path",
+        before.ca_cert_path.as_deref(),
+        incoming.ca_cert_path.as_deref(),
+    )?;
+
+    // Third host path this struct owns, same reasoning: any project with
+    // `allow_docker_access` bind-mounts this path in as the Docker socket
+    // (`project_commands.rs`'s container creation), so an unchecked value
+    // here is a read-write bind mount of whatever it names into every such
+    // project's container.
+    crate::commands::project_commands::validate_mounted_host_path(
+        "Docker socket path",
+        before.docker_socket_path.as_deref(),
+        incoming.docker_socket_path.as_deref(),
+    )?;
+
+    Ok(())
+}
+
 #[tauri::command]
 pub async fn update_settings(
     settings: AppSettings,
     state: State<'_, AppState>,
 ) -> Result<AppSettings, String> {
     let before = state.settings_store.get();
+
+    validate_settings_update(&before, &settings)?;
+
     let saved = state.settings_store.update(settings)?;
 
     // Persisting a setting is not the same as applying it. The gateway is the
@@ -90,7 +150,10 @@ async fn reconcile_gateway(before: &GatewaySettings, after: &GatewaySettings) {
         GatewayAction::StopIfRunning => {
             log::info!("Model gateway disabled in settings — stopping the container");
             if let Err(e) = docker::gateway::stop_gateway_container().await {
-                log::error!("Failed to stop the model gateway after it was disabled: {}", e);
+                log::error!(
+                    "Failed to stop the model gateway after it was disabled: {}",
+                    e
+                );
             }
         }
         GatewayAction::RestartIfRunning => {
@@ -106,10 +169,7 @@ async fn reconcile_gateway(before: &GatewaySettings, after: &GatewaySettings) {
 }
 
 #[tauri::command]
-pub async fn pull_image(
-    image_name: String,
-    app_handle: tauri::AppHandle,
-) -> Result<(), String> {
+pub async fn pull_image(image_name: String, app_handle: tauri::AppHandle) -> Result<(), String> {
     use tauri::Emitter;
     docker::pull_image(&image_name, move |msg| {
         let _ = app_handle.emit("image-pull-progress", msg);
@@ -302,7 +362,10 @@ mod tests {
         let before = enabled_gateway();
         let mut after = before.clone();
         after.enabled = false;
-        assert_eq!(gateway_action(&before, &after), GatewayAction::StopIfRunning);
+        assert_eq!(
+            gateway_action(&before, &after),
+            GatewayAction::StopIfRunning
+        );
         // Still true when it was already off — a stray running container is
         // still a container that shouldn't be up.
         assert_eq!(gateway_action(&after, &after), GatewayAction::StopIfRunning);

app/src-tauri/src/commands/settings_export_commands.rs

@@ -0,0 +1,654 @@
+//! Settings export/import — see triple-c#35.
+//!
+//! Exports the *host* environment (global `AppSettings` plus the global
+//! secrets kept in the OS keychain: the shared Claude Code OAuth login and
+//! the model gateway's two keys), encrypted with a user-chosen password —
+//! see `storage::settings_crypto` for the actual cryptography. Deliberately
+//! out of scope: per-project settings, per-project secrets, and anything
+//! living in a project's Docker volumes.
+//!
+//! **The save/open dialogs are opened from Rust**, the same pattern
+//! `file_commands.rs`'s `pick_save_path`/`pick_files_to_upload` already
+//! establish and document at length: a frontend-driven dialog handing Rust a
+//! host path string is the exact shape of bug that produced this app's past
+//! criticals, so the boundary here is drawn the same place. The frontend can
+//! ask for a picker; it cannot name a host path as an *input*. `preview_
+//! settings_import` resolves the chosen path itself and remembers it
+//! (`AppState::pending_settings_import`) so `apply_settings_import` re-reads
+//! the same file without the path ever crossing back over IPC.
+//!
+//! The *decrypted payload* is not cached between preview and apply — the
+//! password the frontend passes to each call is what it already held for
+//! the first, not a fresh secret extracted from the user, but nothing here
+//! keeps the plaintext itself — export/import secrets included — around for
+//! longer than one command's execution; `apply_settings_import` re-decrypts
+//! the file rather than reusing anything `preview_settings_import` computed.
+//!
+//! **This is new attack surface**: a settings export is a file one person
+//! can hand another and ask them to import, together with a password, and
+//! `apply_settings_import` applies whatever `AppSettings` it decrypts to
+//! wholesale — see the module doc on `models::settings_export` for the
+//! `web_terminal.access_token` carve-out a review of this feature found,
+//! and treat that as the standing example of the class of thing to keep
+//! checking for here, not a one-off fixed bug.
+
+#[cfg(test)]
+use std::path::Path;
+use std::path::PathBuf;
+
+use sha2::{Digest, Sha256};
+use tauri::State;
+use tauri_plugin_dialog::DialogExt;
+use zeroize::Zeroizing;
+
+use crate::models::{
+    AppSettings, ExportedSecrets, SettingsExportPayload, SettingsImportOutcome,
+    SettingsImportPreview, SETTINGS_EXPORT_FORMAT_VERSION,
+};
+use crate::storage::{secure, settings_crypto};
+use crate::AppState;
+
+/// What `preview_settings_import` pins so `apply_settings_import` can tell
+/// whether the file it's about to re-read is the same one the user actually
+/// saw a preview of. Confirming a preview is only meaningful if it's binding
+/// on what gets applied — without this, a file replaced on disk between the
+/// two calls (this app's own stated threat model is a file shared between
+/// people, which may sit in a synced or shared directory) would decrypt and
+/// apply silently different content than what the confirmation dialog showed.
+#[derive(Debug, Clone)]
+pub struct PendingSettingsImport {
+    path: PathBuf,
+    ciphertext_hash: [u8; 32],
+}
+
+fn hash_ciphertext(data: &[u8]) -> [u8; 32] {
+    Sha256::digest(data).into()
+}
+
+const FILE_EXTENSION: &str = "triplec";
+
+/// Enforced here, not only in the export modal: the frontend's minimum is a
+/// UX nudge, but `export_settings` is the actual boundary a weak password
+/// has to cross, and Argon2id's memory-hardness buys little against an
+/// attacker who can just try a three-character password directly.
+const MIN_PASSWORD_LEN: usize = 8;
+
+fn suggested_export_name() -> String {
+    // Timestamped so exporting more than once doesn't silently overwrite an
+    // earlier file just because the save dialog defaults to the same name.
+    format!(
+        "triple-c-settings-{}.{}",
+        chrono::Utc::now().format("%Y%m%d-%H%M%S"),
+        FILE_EXTENSION
+    )
+}
+
+async fn pick_export_save_path(window: &tauri::Window, suggested: &str) -> Option<PathBuf> {
+    let (tx, rx) = tokio::sync::oneshot::channel();
+    window
+        .dialog()
+        .file()
+        .set_parent(window)
+        .set_title("Export Triple-C settings")
+        .set_file_name(suggested)
+        .add_filter("Triple-C settings export", &[FILE_EXTENSION])
+        .save_file(move |picked| {
+            let _ = tx.send(picked);
+        });
+    rx.await.ok().flatten().and_then(|p| p.into_path().ok())
+}
+
+async fn pick_import_open_path(window: &tauri::Window) -> Option<PathBuf> {
+    let (tx, rx) = tokio::sync::oneshot::channel();
+    window
+        .dialog()
+        .file()
+        .set_parent(window)
+        .set_title("Import Triple-C settings")
+        .add_filter("Triple-C settings export", &[FILE_EXTENSION])
+        .pick_file(move |picked| {
+            let _ = tx.send(picked);
+        });
+    rx.await.ok().flatten().and_then(|p| p.into_path().ok())
+}
+
+/// Gather the current global secrets, and hand back the `AppSettings` to
+/// export with the web-terminal token blanked out of it — see the module
+/// doc comment on `models::settings_export` for why that field cannot
+/// travel through `settings` like the rest of this struct.
+///
+/// A missing keychain secret reads as `None` — a keychain read failure is
+/// treated as "nothing to export" for that one entry rather than aborting
+/// the whole export, matching how the rest of this app degrades a keychain
+/// error to "absent" (`has_claude_oauth_token`, `has_gateway_api_key`)
+/// rather than surfacing it as a hard failure.
+fn split_settings_and_secrets(current: AppSettings) -> (AppSettings, ExportedSecrets) {
+    let mut settings = current;
+    let web_terminal_access_token = settings.web_terminal.access_token.take();
+
+    let secrets = ExportedSecrets {
+        claude_oauth_token: secure::get_claude_oauth_token().unwrap_or_default(),
+        gateway_api_key: secure::get_gateway_api_key().unwrap_or_default(),
+        gateway_master_key: secure::get_gateway_master_key().unwrap_or_default(),
+        web_terminal_access_token,
+    };
+
+    (settings, secrets)
+}
+
+/// Export the current global settings and secrets to a password-encrypted
+/// file. `Ok(false)` means the save dialog was dismissed — not an error, and
+/// deliberately distinguishable from one so the frontend shows nothing
+/// rather than a "failed" toast for a plain cancel.
+#[tauri::command]
+pub async fn export_settings(
+    password: String,
+    window: tauri::Window,
+    state: State<'_, AppState>,
+) -> Result<bool, String> {
+    // `.chars().count()` — Unicode scalar values, not bytes — to stay as
+    // close as this pair of languages allows to the frontend's `.length`
+    // check (UTF-16 code units); the two only diverge on astral-plane
+    // characters, which no reasonable password touches.
+    if password.chars().count() < MIN_PASSWORD_LEN {
+        return Err(format!(
+            "Use a password of at least {} characters.",
+            MIN_PASSWORD_LEN
+        ));
+    }
+
+    let Some(dest) = pick_export_save_path(&window, &suggested_export_name()).await else {
+        return Ok(false);
+    };
+
+    let (settings, secrets) = split_settings_and_secrets(state.settings_store.get());
+    if secrets.is_empty() {
+        log::info!("Exporting settings with no global secrets configured on this machine");
+    }
+
+    let payload = SettingsExportPayload {
+        format_version: SETTINGS_EXPORT_FORMAT_VERSION,
+        exported_at: chrono::Utc::now().to_rfc3339(),
+        app_version: env!("CARGO_PKG_VERSION").to_string(),
+        settings,
+        secrets,
+    };
+
+    let plaintext = Zeroizing::new(
+        serde_json::to_vec(&payload)
+            .map_err(|e| format!("Failed to prepare settings for export: {}", e))?,
+    );
+    let encrypted = settings_crypto::encrypt(&plaintext, &password)?;
+
+    std::fs::write(&dest, &encrypted).map_err(|e| format!("Failed to write export file: {}", e))?;
+
+    Ok(true)
+}
+
+/// Open a file picker, decrypt the chosen file with `password`, and return a
+/// preview (counts and presence flags only — never a secret value) for a
+/// confirmation UI. `Ok(None)` means the picker was dismissed.
+///
+/// Remembers the resolved path *and a hash of the file's ciphertext* in
+/// `AppState::pending_settings_import` for `apply_settings_import` to check
+/// against — does **not** remember the decrypted payload itself, so the
+/// password must be supplied again to actually apply it — seeing the preview
+/// is not the same as committing to it. The hash exists so it also can't be
+/// swapped out from under that commitment: `apply_settings_import` refuses to
+/// proceed if the file on disk no longer matches what was just previewed.
+#[tauri::command]
+pub async fn preview_settings_import(
+    password: String,
+    window: tauri::Window,
+    state: State<'_, AppState>,
+) -> Result<Option<SettingsImportPreview>, String> {
+    if password.is_empty() {
+        return Err("A password is required to open a settings export.".to_string());
+    }
+
+    let Some(path) = pick_import_open_path(&window).await else {
+        return Ok(None);
+    };
+
+    let encrypted = std::fs::read(&path).map_err(|e| format!("Failed to read export file: {}", e))?;
+    let payload = read_and_decrypt_bytes(&encrypted, &password)?;
+    let preview = SettingsImportPreview::from_payload(&payload);
+
+    *state.pending_settings_import.lock().await = Some(PendingSettingsImport {
+        path,
+        ciphertext_hash: hash_ciphertext(&encrypted),
+    });
+
+    Ok(Some(preview))
+}
+
+/// Apply the import a prior `preview_settings_import` call resolved a path
+/// for. Fails if no preview is pending — this is not a general "decrypt and
+/// apply this file" entry point, deliberately: seeing the preview first is
+/// required, not just encouraged, since it is the only place a user is told
+/// what an import is about to touch before it touches it. That requirement
+/// is only real if the file can't change out from under it, so this also
+/// refuses to proceed if the file's ciphertext no longer matches the hash
+/// `preview_settings_import` pinned — a file replaced on disk between the
+/// two calls (this feature's own threat model is a file shared between
+/// people, which may sit in a synced or shared directory) must not be able
+/// to apply silently different content than what the confirmation dialog
+/// showed.
+///
+/// Global settings are replaced wholesale — an import is "restore this
+/// environment," not a field-by-field merge. Global secrets are handled
+/// differently and on purpose: **only secrets actually present in the
+/// import are written**; a secret the export doesn't have is left alone on
+/// this machine rather than cleared, because an absent secret in the export
+/// means "the source machine never had this configured," not "delete this
+/// on import." A user who wants to clear a secret already has dedicated UI
+/// for that (signing out of shared auth, clearing the gateway key).
+///
+/// Order matters here, twice over.
+///
+/// First: the imported settings are **validated before any secret is
+/// written**, using the same checks `update_settings` itself runs
+/// (`settings_commands::validate_settings_update`). Restoring a secret is
+/// hard to undo unnoticed — a stale env-var-name rejection or a disallowed
+/// host path used to be caught only when `update_settings` ran, by which
+/// point the three keychain secrets below were already overwritten with the
+/// file's, each with a fresh rotation id, silently flagging every project
+/// container for recreation — while the error the user saw talked only
+/// about the rejected setting and said nothing about the credentials that
+/// had already moved. Failing this check first makes a rejected import
+/// leave nothing touched, matching what "the import failed" is supposed to
+/// mean.
+///
+/// Second, among the things that *do* get written: secrets are restored
+/// **before** the settings replace runs (which is what triggers
+/// `reconcile_gateway`), so a gateway recreation that replace provokes sees
+/// the final key material rather than racing it — restoring the other way
+/// round left a real window where the running gateway and the keychain
+/// briefly disagreed. A gateway *secret* alone (same shape, new key) is
+/// invisible to `reconcile_gateway`'s shape comparison, so this additionally
+/// nudges a running gateway container to recreate itself whenever a secret
+/// this import carried was actually written — otherwise the running
+/// container keeps serving the old key material indefinitely while every
+/// project container is handed the new one.
+///
+/// A keychain write failing is reported back rather than only logged: an
+/// import that silently restores two of three secrets but not the third
+/// must not read as unqualified success.
+///
+/// The pending import is only cleared on success. A failure here (rejected
+/// by the validation above, a stale-file mismatch, or some other error)
+/// leaves it pending so the frontend can let the user retry `apply` without
+/// making them pick the file and re-enter the password again — the
+/// preview's job was confirming *what* to import, not spending the one
+/// attempt at applying it.
+#[tauri::command]
+pub async fn apply_settings_import(
+    password: String,
+    state: State<'_, AppState>,
+) -> Result<SettingsImportOutcome, String> {
+    if password.is_empty() {
+        return Err("A password is required to import settings.".to_string());
+    }
+
+    let pending = state
+        .pending_settings_import
+        .lock()
+        .await
+        .clone()
+        .ok_or_else(|| "No import is pending — choose a file first.".to_string())?;
+
+    let encrypted = std::fs::read(&pending.path)
+        .map_err(|e| format!("Failed to read export file: {}", e))?;
+    if hash_ciphertext(&encrypted) != pending.ciphertext_hash {
+        return Err(
+            "This file changed since you reviewed it — choose it again to see an up-to-date preview."
+                .to_string(),
+        );
+    }
+    let payload = read_and_decrypt_bytes(&encrypted, &password)?;
+
+    let current = state.settings_store.get();
+
+    // The web-terminal token lives inside `AppSettings` itself rather than
+    // the keychain, so "leave an absent secret alone" has to be done by
+    // hand here: carry the destination's current token forward when the
+    // import doesn't have one, instead of letting the wholesale replace
+    // below blank it (every export writes `None` there — see
+    // `split_settings_and_secrets`).
+    let mut settings = payload.settings;
+    settings.web_terminal.access_token = non_blank(payload.secrets.web_terminal_access_token)
+        .or_else(|| current.web_terminal.access_token.clone());
+
+    crate::commands::settings_commands::validate_settings_update(&current, &settings)?;
+
+    let mut secret_restore_warnings = Vec::new();
+    let mut gateway_secret_changed = false;
+
+    if let Some(token) = non_blank(payload.secrets.claude_oauth_token) {
+        if let Err(e) = secure::store_claude_oauth_token(&token) {
+            log::warn!(
+                "Settings import: could not restore the shared Claude login: {}",
+                e
+            );
+            secret_restore_warnings
+                .push(format!("Could not restore your shared Claude login: {}", e));
+        }
+    }
+    if let Some(key) = non_blank(payload.secrets.gateway_api_key) {
+        match secure::store_gateway_api_key(&key) {
+            Ok(()) => gateway_secret_changed = true,
+            Err(e) => {
+                log::warn!(
+                    "Settings import: could not restore the gateway provider API key: {}",
+                    e
+                );
+                secret_restore_warnings.push(format!(
+                    "Could not restore the gateway provider API key: {}",
+                    e
+                ));
+            }
+        }
+    }
+    if let Some(key) = non_blank(payload.secrets.gateway_master_key) {
+        match secure::store_gateway_master_key(&key) {
+            Ok(()) => gateway_secret_changed = true,
+            Err(e) => {
+                log::warn!(
+                    "Settings import: could not restore the gateway master key: {}",
+                    e
+                );
+                secret_restore_warnings
+                    .push(format!("Could not restore the gateway master key: {}", e));
+            }
+        }
+    }
+
+    let saved =
+        crate::commands::settings_commands::update_settings(settings, state.clone()).await?;
+
+    // `reconcile_gateway` (inside `update_settings`) only reacts to a changed
+    // *shape* — port, provider, base URL, models — because that's what's
+    // rendered into the container's config. A secret changing with the shape
+    // held constant is invisible to it, so a running gateway container would
+    // otherwise keep serving the old key material forever after an import
+    // that restored a new one, while `docker::gateway`'s own fingerprint
+    // (which does include the secret rotation id) means the *next* unrelated
+    // settings save would suddenly and confusingly recreate it instead.
+    if gateway_secret_changed && saved.gateway.enabled {
+        match crate::docker::gateway::gateway_container_presence().await {
+            Ok((true, true)) => {
+                if let Err(e) = crate::docker::gateway::ensure_gateway_running(&saved.gateway).await
+                {
+                    log::error!(
+                        "Settings import: could not apply the restored gateway credentials to the running gateway container: {}",
+                        e
+                    );
+                }
+            }
+            Ok(_) => {}
+            Err(e) => log::debug!("Settings import: gateway reconcile skipped ({})", e),
+        }
+    }
+
+    state.pending_settings_import.lock().await.take();
+
+    Ok(SettingsImportOutcome {
+        settings: saved,
+        secret_restore_warnings,
+    })
+}
+
+fn non_blank(value: Option<String>) -> Option<String> {
+    value.filter(|v| !v.trim().is_empty())
+}
+
+/// Only the field `read_and_decrypt` needs before deciding whether the rest
+/// of the payload is even worth attempting to parse.
+#[derive(serde::Deserialize)]
+struct FormatVersionProbe {
+    format_version: u32,
+}
+
+/// Read and decrypt an export file at `path`, then parse it — see
+/// `read_and_decrypt_bytes` for why the format-version check runs before the
+/// full parse. Every real caller already has the file's bytes in hand by the
+/// time it needs this (`preview_settings_import`/`apply_settings_import`
+/// both hash the ciphertext first) and calls `read_and_decrypt_bytes`
+/// directly to avoid reading the file twice; this path-based wrapper only
+/// exists now for tests that don't need that.
+#[cfg(test)]
+fn read_and_decrypt(path: &Path, password: &str) -> Result<SettingsExportPayload, String> {
+    let encrypted =
+        std::fs::read(path).map_err(|e| format!("Failed to read export file: {}", e))?;
+    read_and_decrypt_bytes(&encrypted, password)
+}
+
+/// Decrypt and parse an already-read export file's bytes, checking the
+/// format version **before** attempting to deserialize the full payload.
+///
+/// That ordering is not just tidiness: a version bump that isn't
+/// deserialize-compatible (a field's type changes, not just a new
+/// `#[serde(default)]`-covered one) is exactly the case this check exists
+/// for, and parsing the full struct first would fail on the shape mismatch
+/// before the version check ever ran, surfacing a raw parse error instead
+/// of "update Triple-C" — and, more seriously, `serde_json`'s type-mismatch
+/// errors quote the offending value inline. This file is not attacker
+/// content in the usual sense (it must still decrypt under the right
+/// password), but the plaintext it decrypts to can hold a live credential,
+/// so neither error path below ever interpolates what `serde_json`
+/// actually says — only a fixed, generic message.
+fn read_and_decrypt_bytes(encrypted: &[u8], password: &str) -> Result<SettingsExportPayload, String> {
+    let plaintext = settings_crypto::decrypt(encrypted, password)?;
+
+    let probe: FormatVersionProbe = serde_json::from_slice(&plaintext)
+        .map_err(|_| "This file doesn't look like a valid settings export.".to_string())?;
+    if probe.format_version > SETTINGS_EXPORT_FORMAT_VERSION {
+        return Err(format!(
+            "This export was made by a newer version of Triple-C (format {}, this app supports up to {}). \
+             Update Triple-C before importing it.",
+            probe.format_version, SETTINGS_EXPORT_FORMAT_VERSION
+        ));
+    }
+
+    serde_json::from_slice(&plaintext).map_err(|_| {
+        "This file doesn't look like a valid settings export (unexpected shape).".to_string()
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn non_blank_treats_whitespace_only_as_absent() {
+        assert_eq!(non_blank(Some("   ".to_string())), None);
+        assert_eq!(non_blank(Some("".to_string())), None);
+        assert_eq!(non_blank(None), None);
+        assert_eq!(non_blank(Some(" a ".to_string())), Some(" a ".to_string()));
+    }
+
+    #[test]
+    fn ciphertext_hashing_is_deterministic_and_tamper_sensitive() {
+        // What `apply_settings_import` compares against the pinned hash from
+        // `preview_settings_import` to detect a file swapped out from under a
+        // pending import — this only defends anything if identical bytes
+        // always hash identically and any change to those bytes changes the
+        // hash.
+        let bytes = b"pretend this is an encrypted export file";
+        assert_eq!(hash_ciphertext(bytes), hash_ciphertext(bytes));
+
+        let mut tampered = bytes.to_vec();
+        tampered[0] ^= 0xFF;
+        assert_ne!(hash_ciphertext(bytes), hash_ciphertext(&tampered));
+    }
+
+    fn write_export(
+        dir: &std::path::Path,
+        name: &str,
+        payload: &SettingsExportPayload,
+        password: &str,
+    ) -> PathBuf {
+        write_raw_export(dir, name, &serde_json::to_value(payload).unwrap(), password)
+    }
+
+    /// Like `write_export`, but takes an arbitrary `serde_json::Value` rather
+    /// than a real `SettingsExportPayload` — for fixtures that are
+    /// deliberately not shape-compatible, which the typed helper above can't
+    /// produce at all.
+    fn write_raw_export(
+        dir: &std::path::Path,
+        name: &str,
+        value: &serde_json::Value,
+        password: &str,
+    ) -> PathBuf {
+        let plaintext = serde_json::to_vec(value).unwrap();
+        let encrypted = settings_crypto::encrypt(&plaintext, password).unwrap();
+        let path = dir.join(name);
+        std::fs::write(&path, &encrypted).unwrap();
+        path
+    }
+
+    #[test]
+    fn splitting_settings_moves_the_web_terminal_token_out_rather_than_copying_it() {
+        let mut settings = AppSettings::default();
+        settings.web_terminal.access_token = Some("super-secret-token".to_string());
+
+        let (settings, secrets) = split_settings_and_secrets(settings);
+
+        assert_eq!(settings.web_terminal.access_token, None);
+        assert_eq!(
+            secrets.web_terminal_access_token,
+            Some("super-secret-token".to_string())
+        );
+    }
+
+    #[test]
+    fn splitting_settings_with_no_token_leaves_it_absent_on_both_sides() {
+        let (settings, secrets) = split_settings_and_secrets(AppSettings::default());
+
+        assert_eq!(settings.web_terminal.access_token, None);
+        assert_eq!(secrets.web_terminal_access_token, None);
+    }
+
+    fn sample_payload(format_version: u32) -> SettingsExportPayload {
+        SettingsExportPayload {
+            format_version,
+            exported_at: "2026-08-27T00:00:00Z".to_string(),
+            app_version: "0.4.14".to_string(),
+            settings: AppSettings::default(),
+            secrets: ExportedSecrets::default(),
+        }
+    }
+
+    fn temp_dir(name: &str) -> PathBuf {
+        let dir = std::env::temp_dir().join(format!(
+            "triple-c-settings-export-test-{}-{}",
+            name,
+            uuid::Uuid::new_v4().simple()
+        ));
+        std::fs::create_dir_all(&dir).unwrap();
+        dir
+    }
+
+    #[test]
+    fn a_file_from_a_newer_format_is_refused_before_the_full_shape_is_parsed() {
+        // Shape-incompatible with the *current* `SettingsExportPayload` (a
+        // future version could easily have changed `settings` from an object
+        // to something else) as well as newer — so this only passes under
+        // the probe-first ordering. Parsing the full struct first (the old
+        // behavior) would fail on the shape mismatch and never reach the
+        // version check, producing the "unexpected shape" message instead of
+        // "newer version" / "Update Triple-C".
+        let dir = temp_dir("newer-format");
+        let path = write_raw_export(
+            &dir,
+            "export.triplec",
+            &serde_json::json!({
+                "format_version": SETTINGS_EXPORT_FORMAT_VERSION + 1,
+                "exported_at": "2026-08-27T00:00:00Z",
+                "app_version": "9.9.9",
+                "settings": "this-app-version-stores-settings-differently",
+                "secrets": {},
+            }),
+            "correct password",
+        );
+
+        let err = read_and_decrypt(&path, "correct password").unwrap_err();
+        assert!(err.contains("newer version"), "unexpected message: {}", err);
+        assert!(err.contains("Update Triple-C"));
+
+        std::fs::remove_dir_all(&dir).ok();
+    }
+
+    #[test]
+    fn a_file_at_the_current_format_is_accepted() {
+        let dir = temp_dir("current-format");
+        let path = write_export(
+            &dir,
+            "export.triplec",
+            &sample_payload(SETTINGS_EXPORT_FORMAT_VERSION),
+            "correct password",
+        );
+
+        let payload = read_and_decrypt(&path, "correct password").unwrap();
+        assert_eq!(payload.format_version, SETTINGS_EXPORT_FORMAT_VERSION);
+
+        std::fs::remove_dir_all(&dir).ok();
+    }
+
+    #[test]
+    fn a_malformed_payload_produces_a_generic_error_not_a_raw_serde_message() {
+        // A `format_version` the probe accepts, but a `settings` field of
+        // the wrong *type* rather than just a missing field — this is what
+        // makes `serde_json` produce an "invalid type: string `...`, expected
+        // struct AppSettings" error that quotes the offending value
+        // verbatim. That value here stands in for plaintext that, in a real
+        // export, could be a live credential — the assertion below is only
+        // meaningful against a fixture that actually exercises serde's
+        // value-quoting behavior, which a merely-missing-field fixture does
+        // not.
+        let dir = temp_dir("malformed");
+        let path = write_raw_export(
+            &dir,
+            "export.triplec",
+            &serde_json::json!({
+                "format_version": SETTINGS_EXPORT_FORMAT_VERSION,
+                "exported_at": "2026-08-27T00:00:00Z",
+                "app_version": "0.4.14",
+                "settings": "NOT-A-REAL-CREDENTIAL-abc123",
+                "secrets": {},
+            }),
+            "correct password",
+        );
+
+        let err = read_and_decrypt(&path, "correct password").unwrap_err();
+        assert!(
+            !err.contains("NOT-A-REAL-CREDENTIAL-abc123"),
+            "leaked plaintext into the error: {}",
+            err
+        );
+        assert!(err.contains("doesn't look like a valid settings export"));
+
+        std::fs::remove_dir_all(&dir).ok();
+    }
+
+    #[test]
+    fn the_wrong_password_is_reported_without_a_version_check_ever_running() {
+        let dir = temp_dir("wrong-password");
+        let path = write_export(
+            &dir,
+            "export.triplec",
+            &sample_payload(SETTINGS_EXPORT_FORMAT_VERSION),
+            "correct password",
+        );
+
+        let err = read_and_decrypt(&path, "wrong password").unwrap_err();
+        assert!(
+            err.contains("Wrong password"),
+            "unexpected message: {}",
+            err
+        );
+
+        std::fs::remove_dir_all(&dir).ok();
+    }
+}

app/src-tauri/src/commands/terminal_commands.rs

@@ -6,10 +6,58 @@ use crate::AppState;
 
 /// Build the command to run in the container terminal.
 ///
-/// For Bedrock Profile projects, wraps `claude` in a bash script that validates
-/// the AWS session first. If the SSO session is expired, runs `aws sso login`
-/// so the user can re-authenticate (the URL is clickable via xterm.js WebLinksAddon).
+/// Always a `bash -c` script, because every session runs [`UPDATE_PRELUDE`]
+/// before `exec claude`. For Bedrock Profile projects the script additionally
+/// validates the AWS session first, and runs `aws sso login` if it has expired
+/// so the user can re-authenticate (the URL is clickable via xterm.js
+/// WebLinksAddon).
 fn build_terminal_cmd(project: &Project, state: &AppState, session_name: Option<&str>) -> Vec<String> {
+    let settings = state.settings_store.get();
+    build_claude_terminal_cmd(
+        project,
+        settings.global_aws.aws_profile.as_deref(),
+        session_name,
+    )
+}
+
+/// Shell line run immediately before `exec claude` in every Claude terminal
+/// session.
+///
+/// `container/entrypoint.sh` already runs `claude update` when the container
+/// starts, but containers here use a stop/start (and often just keep running)
+/// model, so a long-lived container's CLI goes stale between restarts. Running
+/// it per session is what keeps a week-old container current.
+///
+/// Deliberately non-fatal and time-bounded: `|| echo` swallows a failure (no
+/// network, npm registry down) so a session always opens, and `timeout 60`
+/// bounds how long a user waits for a terminal.
+///
+/// **`flock` is load-bearing, not tidiness.** Nothing serialises this against
+/// the entrypoint's own `claude update`, and the entrypoint prints "container
+/// ready" only *after* its copy finishes — so "start the project, open a tab"
+/// races two updaters against the same `~/.claude/bin` install, as does
+/// opening two tabs at once. `|| echo` would then hide a half-written install
+/// behind a friendly message and the very next line (`exec claude`) would run
+/// it. `-w 90` gives the entrypoint's `timeout 120` copy room to finish rather
+/// than failing the wait, and `-E 0` makes losing the race a success: the
+/// other holder just updated, so there is nothing left to do.
+pub(crate) const UPDATE_PRELUDE: &str = concat!(
+    "flock -w 90 -E 0 /tmp/.triple-c-claude-update.lock ",
+    r#"timeout 60 claude update 2>&1 || echo "(update skipped — continuing)""#,
+);
+
+/// Single-quote one argument for interpolation into a shell script string.
+fn shell_quote_arg(arg: &str) -> String {
+    format!(" '{}'", arg.replace('\'', "'\\''"))
+}
+
+/// The testable core of [`build_terminal_cmd`], taking the resolved global AWS
+/// profile rather than the whole [`AppState`].
+fn build_claude_terminal_cmd(
+    project: &Project,
+    global_aws_profile: Option<&str>,
+    session_name: Option<&str>,
+) -> Vec<String> {
     let is_bedrock_profile = project.backend == Backend::Bedrock
         && project
             .bedrock_config
@@ -19,36 +67,27 @@ fn build_terminal_cmd(project: &Project, state: &AppState, session_name: Option<
 
     let permission_args = project.effective_permission_mode().cli_args();
 
+    // The args are interpolated into a shell script string, so single-quote
+    // each one.
+    let name_flag = session_name
+        .filter(|n| !n.is_empty())
+        .map(|n| format!(" -n{}", shell_quote_arg(n)))
+        .unwrap_or_default();
+    let permission_flags: String = permission_args.iter().map(|a| shell_quote_arg(a)).collect();
+    let claude_cmd = format!("exec claude{}{}", permission_flags, name_flag);
+
     if !is_bedrock_profile {
-        let mut cmd = vec!["claude".to_string()];
-        cmd.extend(permission_args);
-        if let Some(name) = session_name {
-            if !name.is_empty() {
-                cmd.push("-n".to_string());
-                cmd.push(name.to_string());
-            }
-        }
-        return cmd;
+        return vec![
+            "bash".to_string(),
+            "-c".to_string(),
+            format!("{}\n{}\n", UPDATE_PRELUDE, claude_cmd),
+        ];
     }
 
-    let profile = aws_commands::resolve_profile_for_project(
-        project,
-        state.settings_store.get().global_aws.aws_profile.as_deref(),
-    );
+    let profile = aws_commands::resolve_profile_for_project(project, global_aws_profile);
 
     // Build a bash wrapper that validates credentials, re-auths if needed,
     // then exec's into claude.
-    let name_flag = session_name
-        .filter(|n| !n.is_empty())
-        .map(|n| format!(" -n '{}'", n.replace('\'', "'\\''")))
-        .unwrap_or_default();
-    // The args are interpolated into a shell script string, so single-quote
-    // each one (same escaping style as name_flag above).
-    let permission_flags: String = permission_args
-        .iter()
-        .map(|a| format!(" '{}'", a.replace('\'', "'\\''")))
-        .collect();
-    let claude_cmd = format!("exec claude{}{}", permission_flags, name_flag);
 
     let script = format!(
         r#"
@@ -75,9 +114,11 @@ else
         echo ""
     fi
 fi
+{update_prelude}
 {claude_cmd}
 "#,
         profile = profile,
+        update_prelude = UPDATE_PRELUDE,
         claude_cmd = claude_cmd
     );
 
@@ -197,18 +238,20 @@ pub async fn upload_host_file_to_terminal(
     state: State<'_, AppState>,
 ) -> Result<String, String> {
     // The drop target is a host path chosen by the webview, not by the OS drag
-    // itself, so it gets the same host-read policy as the Files pane's upload:
-    // absolute, no traversal, and nothing out of a hidden directory
-    // (`~/.ssh`, `~/.aws`) or a system location — applied to the path with its
-    // symlinks already resolved, so a visible directory that *leads* to `~/.ssh`
-    // is refused too. What comes back is that resolved path, and it is what
-    // gets opened.
+    // itself, so it goes through `file_commands`' host-read policy: absolute,
+    // no traversal, and nothing whose path passes through a hidden directory
+    // (`~/.ssh`, `~/.aws`, `~/.local/bin`) or a system location — applied to
+    // the path with its symlinks already resolved, so a visible directory that
+    // *leads* to one of those is refused too. What comes back is that resolved
+    // path, and it is what gets opened. Four commands touch a host path now,
+    // but only two take it *over IPC*: this one and `download_container_backup`.
+    // The Files pane's `download_container_file` and `upload_files_to_container`
+    // open their dialog from Rust instead, so for them the policy above is
+    // defence in depth and for these two it is the boundary itself.
     // The name is taken from the path the user actually dropped, *before*
     // resolution. Deriving it from the resolved path renames the file behind
     // the user's back: dropping `~/Downloads/latest.log`, where `latest.log` is
-    // a symlink, would land it in the container as `2026-08-23.log`. The Files
-    // pane's upload had the same bug and fixes it the same way — one helper, so
-    // the two drop targets cannot drift.
+    // a symlink, would land it in the container as `2026-08-23.log`.
     let base = crate::commands::file_commands::host_upload_name(&host_path)?;
     let host_path = crate::commands::file_commands::resolve_host_read_path(&host_path).await?;
 
@@ -217,8 +260,24 @@ pub async fn upload_host_file_to_terminal(
     let meta = tokio::fs::metadata(&host_path)
         .await
         .map_err(|e| format!("Cannot access {}: {}", host_path, e))?;
-    if meta.is_dir() {
-        return Err(format!("{} is a directory — drop individual files", host_path));
+    // `!is_file()`, not `!is_dir()`. A FIFO is neither a directory nor a
+    // regular file, reports `len() == 0`, and passes both the directory check
+    // and the size cap below — and `std::fs::File::open` on one blocks forever
+    // with no writer, with no timeout anywhere on this path. The upload then
+    // never returns, the toast sticks on "Adding N files…" for the session and
+    // the rest of the batch is abandoned. Sockets and device nodes are the same
+    // shape. This is one of two routes for getting a host file into a
+    // container (the Files pane's upload is the other), so it is the wrong
+    // place to be clever.
+    if !meta.is_file() {
+        return Err(if meta.is_dir() {
+            format!("{} is a directory — drop individual files", host_path)
+        } else {
+            format!(
+                "{} is not a regular file — only ordinary files can be dropped into a terminal",
+                host_path
+            )
+        });
     }
 
     // Guard against ballooning host RAM: the file is packed into an in-memory
@@ -229,7 +288,7 @@ pub async fn upload_host_file_to_terminal(
     use crate::docker::exec::MAX_DROP_BYTES;
     if meta.len() > MAX_DROP_BYTES {
         return Err(format!(
-            "File too large to drop into the terminal ({:.0} MB; limit {} MB). Mount it into the project or use the Files panel instead.",
+            "File too large to drop into the terminal ({:.0} MB; limit {} MB). Mount it into the project instead.",
             meta.len() as f64 / (1024.0 * 1024.0),
             MAX_DROP_BYTES / (1024 * 1024)
         ));
@@ -246,7 +305,13 @@ pub async fn upload_host_file_to_terminal(
     .await?;
 
     let file_name = format!("triple-c-drops/{}", base);
-    crate::docker::exec::upload_host_file_to_container(&container_id, &host_path, &file_name).await
+    crate::docker::exec::upload_host_file_to_container(
+        &container_id,
+        &host_path,
+        "/tmp",
+        &file_name,
+    )
+    .await
 }
 
 #[tauri::command]
@@ -301,20 +366,138 @@ pub async fn stop_audio_bridge(
 
 #[cfg(test)]
 mod tests {
-    /// Both drop targets must name a dropped file the way the *user* named it.
+    use super::{build_claude_terminal_cmd, UPDATE_PRELUDE};
+    use crate::models::Project;
+
+    /// A dropped file must be named the way the *user* named it.
     ///
     /// The bug this pins: `upload_host_file_to_terminal` derived the tar entry
     /// name from the path *after* symlink resolution, so dropping
     /// `~/Downloads/latest.log` — where `latest.log` is a symlink to
     /// `2026-08-23.log` — silently landed the file in the container under the
     /// target's name. Nothing errored; the user just got a name they never
-    /// typed. The Files pane had the identical bug.
+    /// typed.
     ///
-    /// What actually keeps the two from drifting is that they now call one
-    /// helper, so this asserts that helper's contract from the terminal side:
-    /// the answer comes from the spelling, and a path that does not name a file
-    /// is refused rather than silently substituted (it used to fall back to
+    /// This asserts the shared helper's contract from the terminal side: the
+    /// answer comes from the spelling, and a path that does not name a file is
+    /// refused rather than silently substituted (it used to fall back to
     /// `"dropped-file"`).
+    /// A `Project` with only the fields these tests care about set; the rest
+    /// come through serde so the test does not have to track every field.
+    fn project(backend: &str, bedrock_config: serde_json::Value) -> Project {
+        serde_json::from_value(serde_json::json!({
+            "id": "p1",
+            "name": "Test",
+            "paths": [],
+            "container_id": null,
+            "status": "running",
+            "backend": backend,
+            "bedrock_config": bedrock_config,
+            "ollama_config": null,
+            "openai_compatible_config": null,
+            "allow_docker_access": false,
+            "full_permissions": false,
+            "ssh_key_path": null,
+            "git_user_name": null,
+            "git_user_email": null,
+            "created_at": "now",
+            "updated_at": "now"
+        }))
+        .expect("test project deserializes")
+    }
+
+    /// Every Claude session updates the CLI before launching it.
+    ///
+    /// `container/entrypoint.sh` only updates at container *start*, and these
+    /// containers are long-lived, so a stale CLI is the normal case without
+    /// this. The plain (non-Bedrock) path therefore has to be a `bash -c`
+    /// wrapper rather than a bare `claude` argv.
+    #[test]
+    fn build_terminal_cmd_updates_before_launching_claude() {
+        let cmd = build_claude_terminal_cmd(&project("anthropic", serde_json::Value::Null), None, None);
+
+        assert_eq!(cmd[0], "bash");
+        assert_eq!(cmd[1], "-c");
+        assert!(
+            cmd[2].contains(UPDATE_PRELUDE),
+            "plain path must run the update prelude: {}",
+            cmd[2]
+        );
+        assert!(cmd[2].contains("exec claude"), "got: {}", cmd[2]);
+        // The update has to happen *before* the exec, which never returns.
+        assert!(
+            cmd[2].find(UPDATE_PRELUDE).unwrap() < cmd[2].find("exec claude").unwrap(),
+            "prelude must precede the exec: {}",
+            cmd[2]
+        );
+        assert!(
+            UPDATE_PRELUDE.contains("timeout 60") && UPDATE_PRELUDE.contains("||"),
+            "the update must stay time-bounded and non-fatal"
+        );
+    }
+
+    /// The session name is interpolated into a shell script, so a quote in it
+    /// must not break out of its single-quoted argument.
+    #[test]
+    fn build_terminal_cmd_escapes_a_quoted_session_name() {
+        let cmd = build_claude_terminal_cmd(
+            &project("anthropic", serde_json::Value::Null),
+            None,
+            Some("Bob's tab; rm -rf /"),
+        );
+
+        assert!(
+            cmd[2].contains(r#"exec claude -n 'Bob'\''s tab; rm -rf /'"#),
+            "session name must be single-quote escaped: {}",
+            cmd[2]
+        );
+    }
+
+    /// Permission flags travel the same escaped path, and an empty name adds
+    /// no `-n` at all.
+    #[test]
+    fn build_terminal_cmd_quotes_permission_flags_and_omits_an_empty_name() {
+        let mut p = project("anthropic", serde_json::Value::Null);
+        p.full_permissions = true;
+        let cmd = build_claude_terminal_cmd(&p, None, Some(""));
+
+        assert!(
+            cmd[2].contains("exec claude '--dangerously-skip-permissions'\n"),
+            "got: {}",
+            cmd[2]
+        );
+        assert!(!cmd[2].contains(" -n "), "empty name must add no flag: {}", cmd[2]);
+    }
+
+    /// The Bedrock-profile path keeps its AWS validation *and* gains the
+    /// prelude, immediately before the exec.
+    #[test]
+    fn build_terminal_cmd_bedrock_validates_aws_and_updates() {
+        let cmd = build_claude_terminal_cmd(
+            &project("bedrock", serde_json::json!({
+                "auth_method": "profile",
+                "aws_region": "us-east-1",
+                "aws_profile": "acme",
+                "model_id": null,
+                "disable_prompt_caching": false
+            })),
+            None,
+            Some("it's fine"),
+        );
+
+        assert_eq!(cmd[0], "bash");
+        let script = &cmd[2];
+        assert!(script.contains("aws sts get-caller-identity --profile 'acme'"), "got: {}", script);
+        assert!(script.contains("triple-c-sso-refresh"), "got: {}", script);
+        assert!(script.contains(UPDATE_PRELUDE), "got: {}", script);
+        assert!(script.contains(r#"exec claude -n 'it'\''s fine'"#), "got: {}", script);
+        assert!(
+            script.find(UPDATE_PRELUDE).unwrap() < script.find("exec claude").unwrap(),
+            "prelude must precede the exec: {}",
+            script
+        );
+    }
+
     #[test]
     fn a_dropped_file_keeps_the_name_the_user_dropped() {
         use crate::commands::file_commands::host_upload_name;

app/src-tauri/src/commands/update_commands.rs

@@ -16,9 +16,37 @@ const REGISTRY_API_BASE: &str =
 const GHCR_TOKEN_URL: &str =
     "https://ghcr.io/token?scope=repository:shadowdao/triple-c-sandbox:pull";
 
+/// The build-time preview suffix, if one was baked in and isn't blank.
+///
+/// The bundle version itself (`tauri.conf.json`, `Cargo.toml`, `package.json`)
+/// is never given a `-preview.<sha>` suffix — `build-app-preview.yml` strips
+/// it before patching those files, because the Windows MSI's `ProductVersion`
+/// is a fixed-width numeric field with no room for one, and nothing here can
+/// verify a change to that without an actual Windows build. `TRIPLE_C_BUILD_SUFFIX`
+/// is the workaround: set as a build-time env var in the preview workflow
+/// only, so `option_env!` bakes it into the binary without the bundle version
+/// ever seeing it. A production build sets nothing, so `option_env!` reads
+/// `None` here — see triple-c#32.
+///
+/// The single source of truth for "is this a preview build": both
+/// `get_app_version()` (what the About panel shows) and `check_for_updates()`
+/// (whether a same-numbered release counts as an update — see `pick_update`)
+/// read this rather than each calling `option_env!` themselves, so the two
+/// can never silently disagree about which build this is.
+fn preview_build_suffix() -> Option<&'static str> {
+    option_env!("TRIPLE_C_BUILD_SUFFIX").filter(|s| !s.is_empty())
+}
+
+fn format_app_version(base: &str, build_suffix: Option<&str>) -> String {
+    match build_suffix {
+        Some(suffix) if !suffix.is_empty() => format!("{}-{}", base, suffix),
+        _ => base.to_string(),
+    }
+}
+
 #[tauri::command]
 pub fn get_app_version() -> String {
-    env!("CARGO_PKG_VERSION").to_string()
+    format_app_version(env!("CARGO_PKG_VERSION"), preview_build_suffix())
 }
 
 #[tauri::command]
@@ -51,30 +79,20 @@ pub async fn check_for_updates() -> Result<Option<UpdateInfo>, String> {
         &[".AppImage", ".deb", ".rpm"]
     };
 
-    // Filter releases that have at least one asset matching the current platform
-    let platform_releases: Vec<&GitHubRelease> = releases
-        .iter()
-        .filter(|r| {
-            r.assets.iter().any(|a| {
-                platform_extensions.iter().any(|ext| a.name.ends_with(ext))
-            })
-        })
-        .collect();
+    // `current_version` above is always the bare, stripped `CARGO_PKG_VERSION`
+    // — the preview workflow patches `Cargo.toml` with that before compiling,
+    // never the `-preview.<sha>`-suffixed one `get_app_version()` reports —
+    // so a preview build and the release it precedes compile to the identical
+    // numeric tuple by construction (see `build-app-preview.yml`'s "highest
+    // tag used, +1" computation). A strict `>` therefore never fires for the
+    // one release a preview most needs to be offered. `is_preview_build`
+    // relaxes that one comparison to `>=` so "there is a real release at my
+    // own number" reads as an update, without touching the production case
+    // — see `pick_update`.
+    let is_preview_build = preview_build_suffix().is_some();
 
-    // Find the latest release with a higher semver version
-    let mut best: Option<(&GitHubRelease, (u32, u32, u32))> = None;
-    for release in &platform_releases {
-        if let Some(ver) = parse_semver_from_tag(&release.tag_name) {
-            if ver > current_semver {
-                if best.is_none() || ver > best.unwrap().1 {
-                    best = Some((release, ver));
-                }
-            }
-        }
-    }
-
-    match best {
-        Some((release, _)) => {
+    match pick_update(&releases, current_semver, platform_extensions, is_preview_build) {
+        Some(release) => {
             // Only include assets matching the current platform
             let assets = release
                 .assets
@@ -105,6 +123,51 @@ pub async fn check_for_updates() -> Result<Option<UpdateInfo>, String> {
     }
 }
 
+/// Pick the newest available update out of a release list, or `None` if
+/// nothing beats `current_semver`. Pure and synchronous — split out of
+/// `check_for_updates` so the prerelease/platform/version filtering can be
+/// tested without a live HTTP call.
+///
+/// Three filters, all of which must pass: not a prerelease (see the long
+/// comment on `GitHubRelease::prerelease`), at least one asset for this
+/// platform, and a tag that parses as semver *and* beats what is running. A
+/// tag that does not parse — `preview-<sha>` (the shape
+/// `build-app-preview.yml` actually creates release tags with), most
+/// realistically — is skipped rather than erroring, the same as it always
+/// has been; nothing here changes what an update tag is expected to look
+/// like, only what channel it is allowed to come from.
+///
+/// `is_preview_build` relaxes "beats" from `>` to `>=`. A preview build's
+/// `current_semver` is the bare number it was compiled with, which is by
+/// construction identical to the release it precedes — see the comment at
+/// `check_for_updates`'s call site — so a strict `>` would never fire for
+/// exactly the release a preview install most needs to be told about.
+fn pick_update<'a>(
+    releases: &'a [GitHubRelease],
+    current_semver: (u32, u32, u32),
+    platform_extensions: &[&str],
+    is_preview_build: bool,
+) -> Option<&'a GitHubRelease> {
+    releases
+        .iter()
+        .filter(|r| !r.prerelease)
+        .filter(|r| {
+            r.assets
+                .iter()
+                .any(|a| platform_extensions.iter().any(|ext| a.name.ends_with(ext)))
+        })
+        .filter_map(|r| parse_semver_from_tag(&r.tag_name).map(|ver| (r, ver)))
+        .filter(|(_, ver)| {
+            if is_preview_build {
+                *ver >= current_semver
+            } else {
+                *ver > current_semver
+            }
+        })
+        .max_by_key(|(_, ver)| *ver)
+        .map(|(r, _)| r)
+}
+
 /// Parse a semver string like "0.2.5" -> (0, 2, 5)
 fn parse_semver(version: &str) -> Option<(u32, u32, u32)> {
     let clean = version.trim_start_matches('v');
@@ -131,6 +194,120 @@ fn extract_version_from_tag(tag: &str) -> Option<String> {
     Some(format!("{}.{}.{}", major, minor, patch))
 }
 
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::models::GitHubAsset;
+
+    // ── format_app_version ──────────────────────────────────────────────
+
+    #[test]
+    fn a_production_build_reports_the_bare_version() {
+        assert_eq!(format_app_version("0.4.12", None), "0.4.12");
+        // An empty env var (set but blank) must not print a trailing dash.
+        assert_eq!(format_app_version("0.4.12", Some("")), "0.4.12");
+    }
+
+    #[test]
+    fn a_preview_build_reports_its_suffix() {
+        assert_eq!(
+            format_app_version("0.4.12", Some("preview.a1b2c3d")),
+            "0.4.12-preview.a1b2c3d"
+        );
+    }
+
+    // ── pick_update ──────────────────────────────────────────────────────
+
+    fn release(tag: &str, prerelease: bool, asset_names: &[&str]) -> GitHubRelease {
+        GitHubRelease {
+            tag_name: tag.to_string(),
+            html_url: format!("https://example.invalid/{}", tag),
+            body: String::new(),
+            assets: asset_names
+                .iter()
+                .map(|name| GitHubAsset {
+                    name: name.to_string(),
+                    browser_download_url: String::new(),
+                    size: 0,
+                })
+                .collect(),
+            published_at: "2026-01-01T00:00:00Z".to_string(),
+            prerelease,
+        }
+    }
+
+    const LINUX_EXTENSIONS: &[&str] = &[".AppImage", ".deb", ".rpm"];
+
+    #[test]
+    fn a_prerelease_is_never_offered_even_if_its_tag_would_otherwise_win() {
+        let releases = vec![release("v9.9.9", true, &["app-9.9.9.AppImage"])];
+        assert!(pick_update(&releases, (0, 4, 10), LINUX_EXTENSIONS, false).is_none());
+    }
+
+    #[test]
+    fn a_release_with_no_asset_for_this_platform_is_skipped() {
+        let releases = vec![release("v0.4.12", false, &["app-0.4.12.msi"])];
+        assert!(pick_update(&releases, (0, 4, 10), LINUX_EXTENSIONS, false).is_none());
+    }
+
+    #[test]
+    fn a_release_that_is_not_newer_is_not_offered() {
+        let releases = vec![release("v0.4.10", false, &["app.AppImage"])];
+        assert!(pick_update(&releases, (0, 4, 10), LINUX_EXTENSIONS, false).is_none());
+    }
+
+    #[test]
+    fn an_untagged_or_unparseable_release_is_skipped_not_fatal() {
+        // A `-preview.<sha>` tag is exactly the shape this must not choke on
+        // or mistake for an update — it simply never parses as a bare semver.
+        let releases = vec![
+            release("preview-a1b2c3d", false, &["app.AppImage"]),
+            release("v0.4.12", false, &["app.AppImage"]),
+        ];
+        let best = pick_update(&releases, (0, 4, 10), LINUX_EXTENSIONS, false).unwrap();
+        assert_eq!(best.tag_name, "v0.4.12");
+    }
+
+    #[test]
+    fn the_highest_qualifying_version_wins_not_the_first_or_last_in_the_list() {
+        let releases = vec![
+            release("v0.4.11", false, &["app.AppImage"]),
+            release("v0.4.13", false, &["app.AppImage"]),
+            release("v0.4.12", false, &["app.AppImage"]),
+        ];
+        let best = pick_update(&releases, (0, 4, 10), LINUX_EXTENSIONS, false).unwrap();
+        assert_eq!(best.tag_name, "v0.4.13");
+    }
+
+    // ── is_preview_build (>= instead of >) ─────────────────────────────────
+
+    /// The exact scenario triple-c#32 was filed to fix: a preview compiled as
+    /// `0.4.12-preview.<sha>` (bare `CARGO_PKG_VERSION` "0.4.12") must be
+    /// offered the `v0.4.12` release that follows it, even though the two
+    /// compute to the identical numeric tuple.
+    #[test]
+    fn a_preview_build_is_offered_the_release_it_precedes() {
+        let releases = vec![release("v0.4.12", false, &["app.AppImage"])];
+        assert!(pick_update(&releases, (0, 4, 12), LINUX_EXTENSIONS, false).is_none());
+        let best = pick_update(&releases, (0, 4, 12), LINUX_EXTENSIONS, true).unwrap();
+        assert_eq!(best.tag_name, "v0.4.12");
+    }
+
+    #[test]
+    fn a_preview_build_is_not_offered_an_older_release() {
+        let releases = vec![release("v0.4.11", false, &["app.AppImage"])];
+        assert!(pick_update(&releases, (0, 4, 12), LINUX_EXTENSIONS, true).is_none());
+    }
+
+    #[test]
+    fn a_production_build_still_requires_strictly_newer() {
+        // A production build must never treat "equal" as an update — that
+        // would perpetually re-offer the version already running.
+        let releases = vec![release("v0.4.12", false, &["app.AppImage"])];
+        assert!(pick_update(&releases, (0, 4, 12), LINUX_EXTENSIONS, false).is_none());
+    }
+}
+
 /// Check whether a newer container image is available in the registry.
 ///
 /// Compares the local image digest with the remote registry digest using the

app/src-tauri/src/docker/exec.rs

@@ -330,29 +330,58 @@ impl ExecSessionManager {
 /// meant a moment earlier.
 pub const MAX_DROP_BYTES: u64 = 256 * 1024 * 1024;
 
-/// Upload a host file into the container's `/tmp` under `dest_name`. The file is
+/// Upload a host file into `dest_dir` under `dest_name`. The file is
 /// read and packed into the tar inside a blocking task, so the synchronous IO
 /// runs off the async worker. The tar's declared entry size is taken from the
 /// bytes actually read (not a separate `stat`), so a file changing size between
 /// a size check and the read can't desync the header and corrupt the archive.
-/// Returns the in-container path (`/tmp/<dest_name>`).
+/// Returns the in-container path (`<dest_dir>/<dest_name>`).
+///
+/// `dest_dir` must already exist and must already have been checked by the
+/// caller — Docker's archive extractor writes wherever it is pointed. The two
+/// callers both do that first, by different routes because they are answering
+/// different questions: the terminal drop stages into a fixed `/tmp` path it
+/// creates itself, and the Files pane passes the directory the user is looking
+/// at, which `file_commands::resolve_container_dir` has already confirmed
+/// resolves inside `CONTAINER_WRITE_ROOTS`.
 pub async fn upload_host_file_to_container(
     container_id: &str,
     host_path: &str,
+    dest_dir: &str,
     dest_name: &str,
+) -> Result<String, String> {
+    let ids = container_user_ids(container_id).await;
+    upload_host_file_with_ids(container_id, host_path, dest_dir, dest_name, ids).await
+}
+
+/// [`upload_host_file_to_container`] for a caller that already knows the
+/// container user's ids.
+///
+/// `container_user_ids` is a `docker exec`, and the Files pane's upload is a
+/// *selection* — one dialog can hand back twenty files. Resolving the ids per
+/// file made twenty extra round trips to answer the same `id -u` twenty times,
+/// which is seconds of latency for a fact that cannot change inside one
+/// container's lifetime. So the loop resolves once and passes the answer in.
+/// The wrapper above keeps the single-file callers unchanged.
+pub async fn upload_host_file_with_ids(
+    container_id: &str,
+    host_path: &str,
+    dest_dir: &str,
+    dest_name: &str,
+    (uid, gid): (u64, u64),
 ) -> Result<String, String> {
     let host_path = host_path.to_string();
     let dest_name = dest_name.to_string();
     let dest_for_blk = dest_name.clone();
-    let (uid, gid) = container_user_ids(container_id).await;
     let mtime = now_epoch_secs();
 
     let tar_buf = tokio::task::spawn_blocking(move || -> Result<Vec<u8>, String> {
         // The caller resolved this path (`resolve_host_read_path`); opening it
         // is a second trip through the same directories, so the descriptor is
         // checked against the path that was validated before its bytes are
-        // packed into anything. Same policy as the Files pane's upload — this
-        // is the terminal's drop target, and the two must not differ.
+        // packed into anything. Two paths reach here: the terminal's drop
+        // target, and the Files pane's upload via `upload_host_file_with_ids`.
+        // Between them they are how host bytes enter a container.
         let file = std::fs::File::open(&host_path)
             .map_err(|e| format!("Failed to read {}: {}", host_path, e))?;
         crate::commands::file_commands::verify_opened_path(
@@ -381,7 +410,7 @@ pub async fn upload_host_file_to_container(
         .upload_to_container(
             container_id,
             Some(UploadToContainerOptions {
-                path: "/tmp".to_string(),
+                path: dest_dir.to_string(),
                 ..Default::default()
             }),
             tar_buf.into(),
@@ -389,7 +418,17 @@ pub async fn upload_host_file_to_container(
         .await
         .map_err(|e| format!("Failed to upload file to container: {}", e))?;
 
-    Ok(format!("/tmp/{}", dest_name))
+    Ok(container_join(dest_dir, &dest_name))
+}
+
+/// Join a container directory to a name that may itself carry separators.
+///
+/// Only the *reported* path — the bytes have already landed by the time this is
+/// called — but that path is what the terminal echoes and what the Files pane
+/// puts in its toast, so `/tmp//x` reading back as a different file than `/tmp/x`
+/// is worth the four lines. `"/"` trims to `""` and yields `/x`.
+fn container_join(dir: &str, name: &str) -> String {
+    format!("{}/{}", dir.trim_end_matches('/'), name.trim_start_matches('/'))
 }
 
 /// Write `data` into the container at `<dest_dir>/<file_name>` with `mode`.
@@ -601,44 +640,6 @@ pub async fn exec_oneshot_as(
     exec_oneshot_inner(container_id, user, cmd, env, MAX_ONESHOT_OUTPUT).await
 }
 
-/// [`exec_oneshot_as`] with a wall-clock ceiling on the whole call.
-///
-/// H8. Nothing in this module bounds how long a container command may take,
-/// which is right for the callers that need it — a base-image migration replays
-/// `apt-get` and takes minutes — and wrong for a short command that can be made
-/// to block forever by a *file* the caller does not control. The upload
-/// reservation is the one that bit: a shell redirect onto a FIFO blocks in
-/// `open(2)` until a reader appears, so a single `mkfifo` in a project
-/// directory left the Files pane on "Uploading…" for the rest of the session
-/// with the rest of the batch abandoned.
-///
-/// So the ceiling is opt-in per call site rather than global. Note what it can
-/// and cannot do: dropping the future closes our end of the stream, but Docker
-/// has no "kill an exec" API, so a process that is genuinely wedged stays
-/// wedged in the container's process table. That is why the primitive matters
-/// more than the timeout — this turns "the app never comes back" into "that
-/// upload failed", and it is the caller's job not to run something that blocks.
-pub async fn exec_oneshot_as_within(
-    container_id: &str,
-    user: &str,
-    cmd: Vec<String>,
-    env: Vec<String>,
-    limit: std::time::Duration,
-) -> Result<(String, i64), String> {
-    match tokio::time::timeout(
-        limit,
-        exec_oneshot_inner(container_id, user, cmd, env, MAX_ONESHOT_OUTPUT),
-    )
-    .await
-    {
-        Ok(result) => result,
-        Err(_) => Err(format!(
-            "The container did not answer within {}s — the command may still be running inside it.",
-            limit.as_secs()
-        )),
-    }
-}
-
 /// What a one-shot exec printed, with the two streams still tellable apart.
 ///
 /// `combined` is stdout and stderr interleaved in arrival order — the shape
@@ -817,8 +818,17 @@ pub async fn wait_for_exec_exit(exec_id: &str) -> Option<i64> {
         match docker.inspect_exec(exec_id).await {
             Ok(info) => {
                 if info.running != Some(true) {
-                    // Finished: use the reported code (default 0 if somehow absent).
-                    return Some(info.exit_code.unwrap_or(0));
+                    // Finished. `exit_code` rather than `unwrap_or(0)`: an exec
+                    // that has stopped without a reported code is a status
+                    // nobody can vouch for, and flattening it to *success* is
+                    // the wrong default when a caller is deciding whether to
+                    // rename a downloaded file over the user's own.
+                    // `download_container_file` treats `None` as a failure
+                    // precisely because it cannot tell that silence from a
+                    // clean exit; an `unwrap_or` here made that check
+                    // unreachable. Callers that only care about "did it fail
+                    // loudly" use `is_some_and`, which reads `None` as before.
+                    return info.exit_code;
                 }
             }
             Err(_) => return None,
@@ -930,4 +940,25 @@ mod tests {
         // …but still comfortably above a genuine /proc/net/tcp{,6} pair.
         assert!(PROC_NET_OUTPUT_LIMIT > 100 * 150);
     }
+
+    /// The reported path, which is what the terminal echoes back to Claude and
+    /// what the Files pane puts in its log line. `/tmp//x` and `/tmp/x` are the
+    /// same file to the kernel and different strings to a person reading either
+    /// of those.
+    #[test]
+    fn container_join_produces_one_separator() {
+        assert_eq!(container_join("/tmp", "a.txt"), "/tmp/a.txt");
+        // The terminal's drop passes a nested name; it must not gain a second
+        // slash at the seam.
+        assert_eq!(
+            container_join("/tmp", "triple-c-drops/a.txt"),
+            "/tmp/triple-c-drops/a.txt"
+        );
+        // A directory the user navigated to can carry a trailing slash, and the
+        // container root is the case where trimming it must not eat the only
+        // separator there is.
+        assert_eq!(container_join("/workspace/", "a.txt"), "/workspace/a.txt");
+        assert_eq!(container_join("/", "a.txt"), "/a.txt");
+        assert_eq!(container_join("/", "/a.txt"), "/a.txt");
+    }
 }

app/src-tauri/src/docker/migration.rs

@@ -369,6 +369,15 @@ pub fn set_delta(from: &BTreeSet<String>, base: &BTreeSet<String>) -> Vec<String
 pub fn bind_mount_exclusions(paths: &[ProjectPath]) -> Vec<String> {
     let mut out: Vec<String> = paths
         .iter()
+        // **The same filter `project_path_mounts` applies, and it has to be.**
+        // That function skips a row with an empty `host_path` or `mount_name`
+        // so a legacy row cannot brick the create. The consequence is that
+        // `/workspace/<name>` for such a row is *not* a bind mount — it is
+        // ordinary writable-layer content. Excluding it here would tell
+        // `compute_verbatim_paths` to skip staging it, and the container swap
+        // would then destroy whatever the user has put there. The two
+        // predicates must agree or a migration silently eats a directory.
+        .filter(|p| !p.mount_name.trim().is_empty() && !p.host_path.trim().is_empty())
         .map(|p| format!("/workspace/{}", p.mount_name))
         .collect();
     out.sort();
@@ -877,6 +886,100 @@ pub async fn reap_probe_containers() {
     }
 }
 
+/// Remove throwaway images left behind by a staleness probe of a stopped
+/// container — [`super::container::commit_container_for_probe`]'s commits.
+///
+/// **Load-bearing, not tidying.** A probe image is *tagged*, because bollard
+/// gives no image id back from a commit and there has to be something to probe.
+/// Tagged means not dangling, so [`super::container::sweep_orphaned_snapshots`]
+/// — which collects every other kind of orphan this app can leave — will never
+/// see one. Without this, a probe that dies between its commit and its own
+/// cleanup (SIGKILL, a crash, a 409 from a concurrent remove) strands a
+/// multi-gigabyte image that **no code path can ever reclaim**, and there is no
+/// UI to find it either. That is the one leak in this app with no floor on it,
+/// so this runs at startup beside [`reap_probe_containers`].
+///
+/// Age-gated for exactly the reason that one is: `reference=` is a daemon-wide
+/// filter, so a second copy of the app probing a project on the same daemon has
+/// images matching this glob, and removing one mid-capture fails that probe with
+/// "No such image" — the bogus `probe_error` the staleness work exists to get
+/// rid of. In-process state cannot see the other instance, so age is the only
+/// brake, and [`PROBE_REAP_MIN_AGE_SECS`] is already the right one: a probe is a
+/// `find` over a root filesystem, not a multi-minute job.
+///
+/// Never fails the caller. Housekeeping, like every other sweep here.
+pub async fn reap_probe_images() {
+    use bollard::image::{ListImagesOptions, RemoveImageOptions};
+
+    let docker = match get_docker() {
+        Ok(d) => d,
+        Err(e) => {
+            log::warn!("Could not reap leftover probe images: {}", e);
+            return;
+        }
+    };
+
+    let filters = HashMap::from([(
+        "reference".to_string(),
+        vec![format!("{}*", super::container::PROBE_IMAGE_PREFIX)],
+    )]);
+    let images = match docker
+        .list_images(Some(ListImagesOptions {
+            all: false,
+            filters,
+            ..Default::default()
+        }))
+        .await
+    {
+        Ok(images) => images,
+        Err(e) => {
+            log::warn!("Could not list leftover probe images: {}", e);
+            return;
+        }
+    };
+
+    let now = chrono::Utc::now().timestamp();
+    for image in images {
+        // Unlike a container summary, an image summary always carries a
+        // `Created`, so there is no unknown-age case to defend against here.
+        if now - image.created < PROBE_REAP_MIN_AGE_SECS {
+            log::info!(
+                "Leaving probe image {:?} alone — it is younger than {} minutes, so it may belong \
+                 to another Triple-C instance's live probe",
+                image.repo_tags,
+                PROBE_REAP_MIN_AGE_SECS / 60
+            );
+            continue;
+        }
+        // By **tag**, never by image id. A `force` removal by id untags an
+        // image everywhere, so an id that happens to carry another name loses
+        // that name too — which is how a test fixture that tagged
+        // `alpine:latest` into this namespace deleted the user's alpine. A real
+        // leftover has exactly the one probe tag, so removing the tag removes
+        // the image; anything else keeps whatever other names it has.
+        for tag in image
+            .repo_tags
+            .iter()
+            .filter(|t| t.starts_with(super::container::PROBE_IMAGE_PREFIX))
+        {
+            log::info!("Removing leftover probe image {}", tag);
+            if let Err(e) = docker
+                .remove_image(
+                    tag,
+                    Some(RemoveImageOptions {
+                        force: true,
+                        noprune: false,
+                    }),
+                    None,
+                )
+                .await
+            {
+                log::warn!("Could not remove leftover probe image {}: {}", tag, e);
+            }
+        }
+    }
+}
+
 /// How old a `triple-c.probe=migration` container must be before
 /// [`reap_probe_containers`] will force-remove it, in seconds.
 ///
@@ -984,6 +1087,119 @@ pub async fn manifest_from_container(container_id: &str) -> Result<Manifest, Str
     Ok(parse_manifest(&out))
 }
 
+/// Cached stopped-container manifests, keyed by container id, each paired with
+/// the container's `FinishedAt` at the time it was captured.
+///
+/// **Sound because a stopped container's writable layer cannot change.** Nothing
+/// can write to it while it is not running, so a manifest captured after it
+/// stopped stays true until it is started again — and `FinishedAt` moves on
+/// every stop, which is what makes the key exact rather than merely plausible.
+///
+/// This exists because `get_container_staleness` is called from a `useEffect`
+/// that fires whenever the container settles, so simply opening a stopped
+/// project's Overview probes it. Uncached that meant a `docker commit` of the
+/// whole writable layer per visit — measured at 44 s on a real project — where
+/// before this feature the same visit cost one throwaway container or nothing at
+/// all. A regression like that is not worth the answer it buys.
+///
+/// Capped, because a `Manifest` of a real container is a few MB: this only has
+/// to serve "the project whose page is open", so a handful of entries is the
+/// whole working set and the oldest is dropped past that.
+static STOPPED_MANIFEST_CACHE: std::sync::Mutex<
+    Option<Vec<(String, String, Manifest)>>,
+> = std::sync::Mutex::new(None);
+
+/// How many stopped-container manifests [`STOPPED_MANIFEST_CACHE`] keeps.
+const STOPPED_MANIFEST_CACHE_MAX: usize = 4;
+
+/// `FinishedAt` for a container, the cache's validity token. `None` when it
+/// cannot be read, which is never treated as a hit.
+async fn container_finished_at(container_id: &str) -> Option<String> {
+    let docker = get_docker().ok()?;
+    docker
+        .inspect_container(container_id, None)
+        .await
+        .ok()?
+        .state?
+        .finished_at
+        .filter(|s| !s.is_empty())
+}
+
+/// Capture a [`Manifest`] from a **stopped** container, reusing a cached one
+/// when the container has not been started since it was taken.
+///
+/// See [`STOPPED_MANIFEST_CACHE`] for why this is exact and why it is needed.
+pub async fn manifest_from_stopped_container_cached(
+    container_id: &str,
+) -> Result<Manifest, String> {
+    let finished_at = container_finished_at(container_id).await;
+
+    if let Some(token) = &finished_at {
+        let guard = STOPPED_MANIFEST_CACHE.lock();
+        if let Ok(cache) = guard {
+            if let Some(entries) = cache.as_ref() {
+                if let Some((_, _, manifest)) = entries
+                    .iter()
+                    .find(|(id, tok, _)| id == container_id && tok == token)
+                {
+                    log::debug!(
+                        "Reusing the cached manifest for stopped container {}",
+                        container_id
+                    );
+                    return Ok(manifest.clone());
+                }
+            }
+        }
+    }
+
+    let manifest = manifest_from_stopped_container(container_id).await?;
+
+    // Only cacheable if the container's state could be read at all; an unknown
+    // `FinishedAt` means there is no token that could later be compared.
+    if let Some(token) = finished_at {
+        if let Ok(mut cache) = STOPPED_MANIFEST_CACHE.lock() {
+            let entries = cache.get_or_insert_with(Vec::new);
+            entries.retain(|(id, _, _)| id != container_id);
+            entries.push((container_id.to_string(), token, manifest.clone()));
+            while entries.len() > STOPPED_MANIFEST_CACHE_MAX {
+                entries.remove(0);
+            }
+        }
+    }
+
+    Ok(manifest)
+}
+
+/// Capture a [`Manifest`] from a **stopped** container.
+///
+/// Commits the container's writable layer to a throwaway image, probes that,
+/// and removes it. This is as current as [`manifest_from_container`] — it reads
+/// the same filesystem — and it is why a stopped project no longer has to fall
+/// back to its snapshot image, which may not exist at all and lags the
+/// container by everything installed since the last commit when it does.
+///
+/// The image is removed on every path, including a failed probe. See
+/// [`super::container::commit_container_for_probe`] for what a crash in the
+/// window between the two costs, and why it is bounded.
+pub async fn manifest_from_stopped_container(container_id: &str) -> Result<Manifest, String> {
+    let image = super::container::commit_container_for_probe(container_id).await?;
+
+    let manifest = manifest_from_image(&image)
+        .await
+        .map_err(|e| format!("Probe of the stopped container did not complete: {}", e));
+
+    if let Err(e) = super::container::remove_image_by_name(&image).await {
+        log::warn!(
+            "Could not remove the staleness probe's throwaway image {}: {} — `reap_probe_images` \
+             collects it at the next app start; the orphan sweep never will, because it is tagged",
+            image,
+            e
+        );
+    }
+
+    manifest
+}
+
 /// The image ID (`sha256:…`) of a local image, or `None` if it is not present.
 ///
 /// Deliberately the **ID**, not a repo digest: locally built images and custom
@@ -1368,6 +1584,30 @@ pub fn parse_preflight(raw: &str) -> PreflightEnvironment {
 
 #[cfg(test)]
 mod tests {
+
+    /// The mount filter and the migration's exclusion list must agree.
+    ///
+    /// `project_path_mounts` skips a row with an empty `host_path` so a legacy
+    /// row cannot brick the create. That makes `/workspace/<name>` ordinary
+    /// writable-layer content rather than a bind mount — and if this function
+    /// still excluded it, `compute_verbatim_paths` would skip staging it and
+    /// the container swap would destroy whatever is there. A migration eating a
+    /// directory is the quietest kind of data loss there is.
+    #[test]
+    fn an_unmountable_row_is_not_excluded_from_the_migration_payload() {
+        let paths = vec![
+            ProjectPath { host_path: "/home/u/code".into(), mount_name: "code".into() },
+            // Legacy shapes that `project_path_mounts` skips.
+            ProjectPath { host_path: "".into(), mount_name: "data".into() },
+            ProjectPath { host_path: "/home/u/x".into(), mount_name: "  ".into() },
+        ];
+        let excluded = bind_mount_exclusions(&paths);
+        assert_eq!(
+            excluded,
+            vec!["/workspace/code".to_string()],
+            "only rows that are actually mounted may be excluded from staging"
+        );
+    }
     use super::*;
     use crate::models::{
         MIGRATION_PHASE_AWAITING, MIGRATION_PHASE_INTERRUPTED, MIGRATION_PHASE_IN_PROGRESS,
@@ -2113,4 +2353,258 @@ mod tests {
         assert!(!pin_is_reapable("pre-migration-handmade", false, ancient, &now));
         assert!(!pin_is_reapable("latest", false, ancient, &now));
     }
+
+    // ── Live Docker ─────────────────────────────────────────────────────────
+
+    /// The cache serves a second read of an unchanged stopped container, and —
+    /// the half that matters — stops serving it the moment the container is
+    /// started and stopped again. If invalidation were wrong this would report a
+    /// filesystem the project no longer has, and a migration would be planned
+    /// against it.
+    ///
+    /// ```text
+    /// cargo test -- --ignored --nocapture stopped_manifest_cache
+    /// ```
+    #[cfg(unix)]
+    #[tokio::test]
+    #[ignore = "needs a Docker daemon; creates, commits and removes a throwaway container"]
+    async fn the_stopped_manifest_cache_survives_a_reread_but_not_a_restart() {
+        fn docker_cli(args: &[&str]) -> String {
+            let out = std::process::Command::new("docker")
+                .args(args)
+                .output()
+                .expect("docker CLI");
+            assert!(
+                out.status.success(),
+                "docker {:?} failed: {}",
+                args,
+                String::from_utf8_lossy(&out.stderr)
+            );
+            String::from_utf8_lossy(&out.stdout).trim().to_string()
+        }
+
+        let image = std::env::var("TRIPLE_C_TEST_IMAGE")
+            .unwrap_or_else(|_| "ghcr.io/shadowdao/triple-c-sandbox:latest".to_string());
+        let first = format!("/opt/cache-marker-a-{}", std::process::id());
+        let second = format!("/opt/cache-marker-b-{}", std::process::id());
+
+        let id = docker_cli(&[
+            "run", "-d", "--label", "triple-c.managed=true",
+            "--entrypoint", "/bin/sh",
+            &image, "-c", "sleep 600",
+        ]);
+        let cleanup = || {
+            let _ = std::process::Command::new("docker")
+                .args(["rm", "-f", &id])
+                .output();
+        };
+
+        docker_cli(&["exec", &id, "mkdir", "-p", &first]);
+        docker_cli(&["stop", "-t", "1", &id]);
+
+        let t0 = std::time::Instant::now();
+        let cold = manifest_from_stopped_container_cached(&id).await;
+        let cold_ms = t0.elapsed().as_millis();
+
+        let t1 = std::time::Instant::now();
+        let warm = manifest_from_stopped_container_cached(&id).await;
+        let warm_ms = t1.elapsed().as_millis();
+
+        // Restart, change the filesystem, stop again — `FinishedAt` moves.
+        docker_cli(&["start", &id]);
+        docker_cli(&["exec", &id, "mkdir", "-p", &second]);
+        docker_cli(&["stop", "-t", "1", &id]);
+        let after_restart = manifest_from_stopped_container_cached(&id).await;
+
+        cleanup();
+
+        let has = |m: &Manifest, p: &str| m.paths.iter().any(|e| e.path == p && e.is_dir());
+
+        let cold = cold.expect("cold read");
+        let warm = warm.expect("warm read");
+        let after_restart = after_restart.expect("read after restart");
+
+        assert!(has(&cold, &first), "cold read missed {}", first);
+        assert!(has(&warm, &first), "warm read missed {}", first);
+        println!("cold {} ms, warm {} ms", cold_ms, warm_ms);
+        assert!(
+            warm_ms * 5 < cold_ms.max(5),
+            "the second read cost {} ms against a cold {} ms — it re-committed \
+             instead of using the cache",
+            warm_ms,
+            cold_ms
+        );
+
+        // The restart must have invalidated it: the new directory has to show up.
+        assert!(
+            has(&after_restart, &second),
+            "a restart did not invalidate the cache — {} is missing, so this is \
+             a stale manifest of a filesystem the container no longer has",
+            second
+        );
+        assert!(has(&after_restart, &first), "the restart lost {}", first);
+    }
+
+    /// The reaper finds a leftover probe image by prefix and — crucially —
+    /// refuses to remove a young one, because that image may be another
+    /// Triple-C instance's live probe. Only a real daemon can say whether the
+    /// `reference=` glob matches the names `get_probe_image_name` produces.
+    ///
+    /// The fixture is **committed**, not tagged and not built. An image's
+    /// `Created` is its own, not its tag's, so tagging something already on disk
+    /// into this namespace yields a fixture the reaper is right to call ancient
+    /// — and BuildKit stamps a fixed epoch on `docker build` output, so a built
+    /// one looks ancient too. A commit stamps *now*, verified against Engine
+    /// 29.6, which is also how real probe images get their age.
+    ///
+    /// Both of those mistakes were made here first, and one of them deleted an
+    /// unrelated `alpine:latest` — which is why `reap_probe_images` removes by
+    /// tag rather than by image id.
+    ///
+    /// ```text
+    /// cargo test -- --ignored --nocapture reaper_spares
+    /// ```
+    #[cfg(unix)]
+    #[tokio::test]
+    #[ignore = "needs a Docker daemon; builds and removes a throwaway image"]
+    async fn the_reaper_spares_a_probe_image_young_enough_to_be_someone_elses() {
+        use std::process::Command;
+
+        fn docker_out(args: &[&str]) -> std::process::Output {
+            Command::new("docker").args(args).output().expect("docker CLI")
+        }
+
+        let base = std::env::var("TRIPLE_C_TEST_IMAGE")
+            .unwrap_or_else(|_| "alpine:latest".to_string());
+        let name = crate::docker::container::get_probe_image_name("reapertest01234");
+
+        // A never-started container is enough to commit from, and leaves the
+        // daemon's run state alone entirely.
+        let created = docker_out(&["create", &base, "true"]);
+        assert!(
+            created.status.success(),
+            "could not create the fixture container from {}: {}",
+            base,
+            String::from_utf8_lossy(&created.stderr)
+        );
+        let cid = String::from_utf8_lossy(&created.stdout).trim().to_string();
+
+        let committed = docker_out(&["commit", "--pause=false", &cid, &name]);
+        let _ = docker_out(&["rm", "-f", &cid]);
+        assert!(
+            committed.status.success(),
+            "could not commit the fixture image: {}",
+            String::from_utf8_lossy(&committed.stderr)
+        );
+
+        reap_probe_images().await;
+
+        let still_there = Command::new("docker")
+            .args(["image", "inspect", &name])
+            .output()
+            .expect("docker image inspect")
+            .status
+            .success();
+
+        let _ = Command::new("docker").args(["rmi", &name]).output();
+
+        assert!(
+            still_there,
+            "a probe image committed seconds ago was reaped — that is another \
+             instance's live probe being broken, see PROBE_REAP_MIN_AGE_SECS"
+        );
+    }
+
+    /// A *stopped* container is readable, and what comes back is its writable
+    /// layer rather than the image it was created from. This is the whole point
+    /// of the function: the base image cannot answer it, and the project may
+    /// well have no snapshot image at all.
+    ///
+    /// Also asserts the throwaway commit leaves nothing behind, which no unit
+    /// test can. It has to assert on the `triple-c-probe-*` tags specifically:
+    /// the probe image is *tagged*, so a leak never shows up as a dangling
+    /// image and a dangling-set assertion here would pass either way.
+    ///
+    /// Ignored because it needs Docker and commits a container; run it with
+    ///
+    /// ```text
+    /// cargo test -- --ignored --nocapture stopped_container
+    /// ```
+    #[cfg(unix)]
+    #[tokio::test]
+    #[ignore = "needs a Docker daemon; creates, commits and removes a throwaway container"]
+    async fn a_stopped_container_is_read_from_its_writable_layer() {
+        fn docker_cli(args: &[&str]) -> String {
+            let out = std::process::Command::new("docker")
+                .args(args)
+                .output()
+                .expect("docker CLI");
+            assert!(
+                out.status.success(),
+                "docker {:?} failed: {}",
+                args,
+                String::from_utf8_lossy(&out.stderr)
+            );
+            String::from_utf8_lossy(&out.stdout).trim().to_string()
+        }
+        fn probe_images() -> Vec<String> {
+            let mut ids: Vec<String> = docker_cli(&[
+                "images", "-q",
+                "--filter",
+                &format!("reference={}*", crate::docker::container::PROBE_IMAGE_PREFIX),
+            ])
+            .lines()
+            .map(|l| l.trim().to_string())
+            .filter(|l| !l.is_empty())
+            .collect();
+            ids.sort();
+            ids
+        }
+
+        let image = std::env::var("TRIPLE_C_TEST_IMAGE")
+            .unwrap_or_else(|_| "ghcr.io/shadowdao/triple-c-sandbox:latest".to_string());
+        // A marker only the writable layer can carry, under a MANIFEST_ROOTS root.
+        let marker = format!("/opt/probe-marker-{}", std::process::id());
+
+        // Another instance's live probe images are allowed to exist; what must
+        // hold is that this probe adds none of its own.
+        let before = probe_images();
+
+        let id = docker_cli(&[
+            "run", "-d", "--label", "triple-c.managed=true",
+            "--entrypoint", "/bin/sh",
+            &image, "-c", "sleep 300",
+        ]);
+        let cleanup = |id: &str| {
+            let _ = std::process::Command::new("docker")
+                .args(["rm", "-f", id])
+                .output();
+        };
+
+        docker_cli(&["exec", &id, "mkdir", "-p", &marker]);
+        docker_cli(&["stop", "-t", "1", &id]);
+
+        let result = manifest_from_stopped_container(&id).await;
+
+        cleanup(&id);
+
+        let manifest = result.expect("a stopped container must be probeable");
+        assert!(
+            manifest.paths.iter().any(|e| e.path == marker && e.is_dir()),
+            "the probe read the image, not the container's writable layer: {} missing",
+            marker
+        );
+        // Non-empty package sets prove the probe script really ran, rather than
+        // parsing an empty transcript into an empty-but-Ok manifest.
+        assert!(
+            !manifest.apt_manual.is_empty(),
+            "apt-mark showmanual came back empty, so the probe did not run"
+        );
+
+        assert_eq!(
+            probe_images(),
+            before,
+            "the throwaway probe image was not cleaned up"
+        );
+    }
 }

app/src-tauri/src/file_viewer/mod.rs

@@ -0,0 +1,109 @@
+//! The terminal file viewer: one OS window per clicked path.
+//!
+//! Every window is a `file-viewer-<n>` label registered in [`registry::ViewerRegistry`];
+//! the commands in `commands/file_viewer_commands.rs` gate on the label and act only on
+//! the caller's own entry, which is why nothing here takes a path from a window.
+//!
+//! `file-viewer-*` is also the `windows` glob of `capabilities/file-viewer.json`, which grants
+//! exactly the five `viewer_*` commands and nothing else. Labels are minted only here; a window
+//! created anywhere else with a matching label would inherit those grants.
+
+pub mod poll;
+pub mod registry;
+pub mod resolve;
+pub mod window;
+pub mod write;
+
+/// Spec §3: the 21st click is refused with a toast.
+pub const MAX_VIEWER_WINDOWS: usize = 20;
+pub const VIEWER_LABEL_PREFIX: &str = "file-viewer-";
+
+pub fn is_viewer_label(label: &str) -> bool {
+    label
+        .strip_prefix(VIEWER_LABEL_PREFIX)
+        .is_some_and(|rest| !rest.is_empty() && rest.bytes().all(|b| b.is_ascii_digit()))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn only_numbered_viewer_labels_pass() {
+        assert!(is_viewer_label("file-viewer-1"));
+        assert!(is_viewer_label("file-viewer-20"));
+        assert!(!is_viewer_label("file-viewer-"));
+        assert!(!is_viewer_label("file-viewer-x"));
+        assert!(!is_viewer_label("main"));
+        assert!(!is_viewer_label("browser-view-abc"));
+    }
+
+    /// Both Vite's dev server and Tauri's asset lookup fall back to `index.html`
+    /// when `viewer.html` is missing, so a broken entry opens the *main app* in
+    /// the viewer window with no error anywhere. Pin the two files the entry needs.
+    #[test]
+    fn the_viewer_entry_exists_and_is_a_vite_input() {
+        let app_dir = std::path::Path::new(env!("CARGO_MANIFEST_DIR")).join("..");
+        let html = std::fs::read_to_string(app_dir.join("viewer.html")).expect("app/viewer.html");
+        assert!(html.contains("/src/viewer/main.tsx"));
+        assert!(!html.contains("<style"), "an inline <style> makes Tauri add a style nonce, which disables 'unsafe-inline' and breaks CodeMirror");
+        let vite = std::fs::read_to_string(app_dir.join("vite.config.ts")).expect("vite.config.ts");
+        assert!(vite.contains("viewer.html"), "vite.config.ts must list viewer.html in build.rollupOptions.input");
+    }
+
+    #[derive(serde::Deserialize)]
+    struct Capability {
+        windows: Vec<String>,
+        permissions: Vec<String>,
+    }
+
+    /// Task 12: a substring check on the capability JSON (the form this test used to take)
+    /// only proves a permission string appears *somewhere* in the file — it would not catch
+    /// `windows` widened past `file-viewer-*`, nor an extra grant slipped in beside the ones
+    /// this window actually needs. Parse both capability files and pin `windows`/`permissions`
+    /// exactly, so a later widening of either file is a failing test, not a silent threat-model
+    /// drift — this file *is* the reviewed threat model of record (see its own description).
+    #[test]
+    fn the_viewer_capability_grants_exactly_the_reviewed_windows_and_permissions() {
+        let app_dir = std::path::Path::new(env!("CARGO_MANIFEST_DIR")).join("..");
+        let raw = std::fs::read_to_string(app_dir.join("src-tauri/capabilities/file-viewer.json"))
+            .expect("capabilities/file-viewer.json");
+        let cap: Capability = serde_json::from_str(&raw).expect("file-viewer.json must be valid JSON");
+
+        assert_eq!(cap.windows, vec!["file-viewer-*"]);
+
+        let mut permissions = cap.permissions;
+        permissions.sort();
+        assert_eq!(
+            permissions,
+            vec![
+                // App commands (bare): the five viewer commands, and nothing else — build.rs
+                // refuses any other bare grant in this file.
+                "allow-viewer-choose-file",
+                "allow-viewer-get-state",
+                "allow-viewer-poll-file",
+                "allow-viewer-read-file",
+                "allow-viewer-write-file",
+                // Plugin/core grants, unchanged.
+                "core:event:allow-listen",
+                "core:event:allow-unlisten",
+                "core:webview:allow-internal-toggle-devtools",
+                "core:window:allow-destroy",
+            ]
+        );
+    }
+
+    /// The main window's capability file must stay scoped to `main` — a `windows` list that
+    /// grew to include `file-viewer-*` would hand every viewer window the dialog/store surface
+    /// `default.json` grants `main`, which is a much larger IPC surface than the one
+    /// `file-viewer.json` was deliberately kept small.
+    #[test]
+    fn the_default_capability_is_scoped_to_the_main_window_only() {
+        let app_dir = std::path::Path::new(env!("CARGO_MANIFEST_DIR")).join("..");
+        let raw = std::fs::read_to_string(app_dir.join("src-tauri/capabilities/default.json"))
+            .expect("capabilities/default.json");
+        let cap: Capability = serde_json::from_str(&raw).expect("default.json must be valid JSON");
+
+        assert_eq!(cap.windows, vec!["main"]);
+    }
+}

app/src-tauri/src/file_viewer/poll.rs

@@ -0,0 +1,194 @@
+//! One cheap exec per tick: the file's full hash and size, or "gone".
+//!
+//! This is what the 2 s poll asks, instead of re-downloading up to 1 MiB of archive per
+//! window per tick. The hash is coreutils `sha256sum`, which equals `write::sha256_hex`
+//! of the bytes whenever the read was not truncated — the only case in which the
+//! editor uses a hash as its save base.
+
+use serde::Serialize;
+
+use crate::docker::exec::exec_oneshot_streams_as;
+
+#[derive(Clone, Debug, Serialize, PartialEq, Eq)]
+pub struct ViewerPoll {
+    pub exists: bool,
+    pub hash: Option<String>,
+    pub size: Option<u64>,
+}
+
+/// Exit 4 = gone. A failure after `test -f` passed is re-checked: if the file vanished
+/// in between (deleted while being hashed), that is "gone", not an error (M6).
+pub const POLL_SCRIPT: &str = r#"test -f "$1" || exit 4
+sha256sum -- "$1" && stat -c %s -- "$1" && exit 0
+test -f "$1" || exit 4
+exit 1"#;
+
+pub fn parse_poll_output(code: i64, stdout: &str) -> ViewerPoll {
+    if code == 4 {
+        return ViewerPoll { exists: false, hash: None, size: None };
+    }
+    let mut lines = stdout.lines();
+    let hash = lines
+        .next()
+        .and_then(|l| l.split_whitespace().next())
+        // GNU `sha256sum` prefixes the line with `\` when the name contains a
+        // backslash or a newline; strip it before validating the hex (P15).
+        .map(|h| h.trim_start_matches('\\'))
+        .filter(|h| super::write::is_sha256_hex(h))
+        .map(str::to_string);
+    let size = lines.next().and_then(|l| l.trim().parse::<u64>().ok());
+    ViewerPoll { exists: true, hash, size }
+}
+
+pub async fn poll_file(container_id: &str, container_path: &str) -> Result<ViewerPoll, String> {
+    let cmd = vec![
+        "sh".to_string(),
+        "-c".to_string(),
+        POLL_SCRIPT.to_string(),
+        "poll".to_string(),
+        container_path.to_string(),
+    ];
+    let (stdout, stderr, code) =
+        exec_oneshot_streams_as(container_id, "claude", cmd, Vec::new()).await?;
+    if code != 0 && code != 4 {
+        return Err(format!(
+            "Could not check the file: {}",
+            crate::commands::file_commands::clip_container_text(&stderr)
+        ));
+    }
+    Ok(parse_poll_output(code, &stdout))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn a_present_file_yields_hash_and_size() {
+        let out = "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855  /workspace/x\n42\n";
+        assert_eq!(
+            parse_poll_output(0, out),
+            ViewerPoll {
+                exists: true,
+                hash: Some("e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855".into()),
+                size: Some(42)
+            }
+        );
+    }
+
+    #[test]
+    fn exit_four_means_gone() {
+        assert_eq!(parse_poll_output(4, ""), ViewerPoll { exists: false, hash: None, size: None });
+    }
+
+    #[test]
+    fn garbage_is_not_a_hash() {
+        let p = parse_poll_output(0, "not a hash  /x\nabc\n");
+        assert_eq!(p, ViewerPoll { exists: true, hash: None, size: None });
+    }
+
+    #[test]
+    fn the_script_tests_existence_before_hashing() {
+        assert!(POLL_SCRIPT.contains("test -f \"$1\" || exit 4"));
+        assert!(POLL_SCRIPT.contains("sha256sum -- \"$1\""));
+        assert!(POLL_SCRIPT.contains("stat -c %s -- \"$1\""));
+    }
+
+    #[cfg(unix)]
+    fn run_poll_script(path_env: Option<&str>, target: &std::path::Path) -> (i64, String, String) {
+        let mut cmd = std::process::Command::new("sh");
+        if let Some(p) = path_env {
+            cmd.env("PATH", p);
+        }
+        let out = cmd.arg("-c").arg(POLL_SCRIPT).arg("poll").arg(target).output().unwrap();
+        (
+            out.status.code().unwrap_or(-1) as i64,
+            String::from_utf8_lossy(&out.stdout).into_owned(),
+            String::from_utf8_lossy(&out.stderr).into_owned(),
+        )
+    }
+
+    #[cfg(unix)]
+    fn test_dir(name: &str) -> std::path::PathBuf {
+        let dir = std::env::temp_dir().join(format!("tc-poll-{}-{}", name, uuid::Uuid::new_v4()));
+        std::fs::create_dir_all(&dir).unwrap();
+        dir
+    }
+
+    #[cfg(unix)]
+    #[test]
+    fn on_the_host_the_poll_script_reports_hash_size_and_gone() {
+        let dir = test_dir("plain");
+        let target = dir.join("t.txt");
+        std::fs::write(&target, b"hello\n").unwrap();
+        let (code, stdout, stderr) = run_poll_script(None, &target);
+        assert_eq!(code, 0, "stderr={stderr}");
+        let p = parse_poll_output(code, &stdout);
+        assert_eq!(p.hash.as_deref(), Some(super::super::write::sha256_hex(b"hello\n").as_str()));
+        assert_eq!(p.size, Some(6));
+
+        let (code, _, _) = run_poll_script(None, &dir.join("missing"));
+        assert_eq!(code, 4);
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    /// M6: the file is deleted after `test -f` passed but before `sha256sum` read it
+    /// (a `sha256sum` shim on PATH deletes it and fails). That is "gone", not an error
+    /// the viewer would have to explain.
+    #[cfg(unix)]
+    #[test]
+    fn on_the_host_a_file_deleted_mid_poll_reads_as_gone() {
+        use std::os::unix::fs::PermissionsExt;
+        let dir = test_dir("race");
+        let bin = dir.join("bin");
+        std::fs::create_dir_all(&bin).unwrap();
+        let shim = bin.join("sha256sum");
+        std::fs::write(&shim, "#!/bin/sh\nrm -f -- \"$2\"\necho 'sha256sum: No such file or directory' >&2\nexit 1\n").unwrap();
+        std::fs::set_permissions(&shim, std::fs::Permissions::from_mode(0o755)).unwrap();
+        let target = dir.join("t.txt");
+        std::fs::write(&target, b"x").unwrap();
+        let path = format!("{}:{}", bin.display(), std::env::var("PATH").unwrap_or_default());
+
+        let (code, stdout, stderr) = run_poll_script(Some(&path), &target);
+
+        assert_eq!(code, 4, "stderr={stderr}");
+        assert_eq!(parse_poll_output(code, &stdout), ViewerPoll { exists: false, hash: None, size: None });
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    /// A failure with the file still present stays a real error (exit 1), which
+    /// `poll_file` turns into "Could not check the file: …".
+    #[cfg(unix)]
+    #[test]
+    fn on_the_host_a_hash_failure_on_a_present_file_is_an_error() {
+        use std::os::unix::fs::PermissionsExt;
+        let dir = test_dir("fail");
+        let bin = dir.join("bin");
+        std::fs::create_dir_all(&bin).unwrap();
+        let shim = bin.join("sha256sum");
+        std::fs::write(&shim, "#!/bin/sh\necho 'sha256sum: Permission denied' >&2\nexit 1\n").unwrap();
+        std::fs::set_permissions(&shim, std::fs::Permissions::from_mode(0o755)).unwrap();
+        let target = dir.join("t.txt");
+        std::fs::write(&target, b"x").unwrap();
+        let path = format!("{}:{}", bin.display(), std::env::var("PATH").unwrap_or_default());
+
+        let (code, _stdout, stderr) = run_poll_script(Some(&path), &target);
+
+        assert_eq!(code, 1, "stderr={stderr}");
+        assert!(stderr.contains("Permission denied"));
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    /// P15: a path containing a backslash makes GNU `sha256sum` prefix the whole
+    /// line with `\`; that must not blind change detection by yielding `hash: None`.
+    #[test]
+    fn a_backslash_prefixed_hash_is_still_recognised() {
+        let out = "\\e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855  /workspace/x\\y\n7\n";
+        let p = parse_poll_output(0, out);
+        assert_eq!(
+            p.hash.as_deref(),
+            Some("e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855")
+        );
+        assert_eq!(p.size, Some(7));
+    }
+}

app/src-tauri/src/file_viewer/registry.rs

@@ -0,0 +1,379 @@
+//! Which viewer window is looking at what.
+//!
+//! Managed with `app.manage(ViewerRegistry::default())` rather than as a field on
+//! `AppState`, like the browser view keeps its own state. A label is reserved *before*
+//! the window is built so two concurrent clicks cannot both pass the cap check.
+
+use std::collections::HashMap;
+use std::sync::atomic::{AtomicU64, Ordering};
+use std::sync::Mutex;
+
+use serde::{Deserialize, Serialize};
+
+use super::{MAX_VIEWER_WINDOWS, VIEWER_LABEL_PREFIX};
+
+#[derive(Clone, Debug, Serialize, Deserialize, PartialEq, Eq, Default)]
+pub struct Location {
+    pub line: Option<u32>,
+    pub col: Option<u32>,
+    pub end_line: Option<u32>,
+}
+
+#[derive(Clone, Debug, Serialize, PartialEq, Eq)]
+#[serde(tag = "kind", rename_all = "snake_case")]
+pub enum ViewerTargetState {
+    Resolved { container_path: String },
+    Choose { candidates: Vec<String> },
+    NotFound { tried: Vec<String> },
+}
+
+#[derive(Clone, Debug, Serialize, PartialEq, Eq)]
+pub struct ViewerTarget {
+    pub project_id: String,
+    pub project_name: String,
+    pub raw_path: String,
+    pub state: ViewerTargetState,
+    pub initial: Location,
+}
+
+/// What [`ViewerRegistry::reserve`] decided.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub enum Reservation {
+    /// A window is already registered on this file. `built` is false while that
+    /// window is still being created: it has no `WebviewWindow` to focus yet, and
+    /// it will open at its own location, so the caller should simply return.
+    Existing { label: String, built: bool },
+    /// A new label, registered and counted against the cap; build its window,
+    /// then call [`ViewerRegistry::mark_built`] (or `remove` if building failed).
+    Reserved(String),
+}
+
+/// What [`ViewerRegistry::choose`] decided.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub enum Choice {
+    /// The caller's entry now points at the chosen file.
+    Resolved(ViewerTarget),
+    /// Another window already has that file; the caller's entry is unchanged.
+    AlreadyOpen { label: String, built: bool },
+}
+
+#[derive(Clone, Debug)]
+struct Entry {
+    target: ViewerTarget,
+    /// Set once the window's `build()` has returned. Until then the label has no
+    /// window by design, so "registered but windowless" means "being built", not
+    /// "stale" — only built entries are ever pruned.
+    built: bool,
+}
+
+#[derive(Default)]
+pub struct ViewerRegistry {
+    entries: Mutex<HashMap<String, Entry>>,
+    next: AtomicU64,
+}
+
+fn same_file(t: &ViewerTarget, project_id: &str, container_path: &str) -> bool {
+    t.project_id == project_id
+        && matches!(&t.state, ViewerTargetState::Resolved { container_path: p } if p == container_path)
+}
+
+fn open_on(
+    entries: &HashMap<String, Entry>,
+    project_id: &str,
+    container_path: &str,
+    except: Option<&str>,
+) -> Option<(String, bool)> {
+    entries
+        .iter()
+        .find(|(label, e)| Some(label.as_str()) != except && same_file(&e.target, project_id, container_path))
+        .map(|(label, e)| (label.clone(), e.built))
+}
+
+/// Drops built entries whose window is gone, whatever their state. `Destroyed`
+/// normally removes an entry; this is the backstop for one it missed, so a leak
+/// can never hold a cap slot for good.
+fn prune(entries: &mut HashMap<String, Entry>, is_live: &dyn Fn(&str) -> bool) {
+    entries.retain(|label, e| !e.built || is_live(label));
+}
+
+impl ViewerRegistry {
+    fn lock(&self) -> std::sync::MutexGuard<'_, HashMap<String, Entry>> {
+        self.entries.lock().unwrap_or_else(|e| e.into_inner())
+    }
+
+    /// Finds the window already open on a resolved target, or reserves a label,
+    /// in one critical section, after pruning built entries `is_live` says are
+    /// gone. `is_live` runs under the registry lock and must not call back into
+    /// the registry.
+    pub fn reserve(
+        &self,
+        target: ViewerTarget,
+        is_live: impl Fn(&str) -> bool,
+    ) -> Result<Reservation, String> {
+        let mut entries = self.lock();
+        prune(&mut entries, &is_live);
+        if let ViewerTargetState::Resolved { container_path } = &target.state {
+            if let Some((label, built)) = open_on(&entries, &target.project_id, container_path, None) {
+                return Ok(Reservation::Existing { label, built });
+            }
+        }
+        if entries.len() >= MAX_VIEWER_WINDOWS {
+            return Err(format!(
+                "{} file windows are already open — close one before opening another.",
+                MAX_VIEWER_WINDOWS
+            ));
+        }
+        let n = self.next.fetch_add(1, Ordering::SeqCst) + 1;
+        let label = format!("{}{}", VIEWER_LABEL_PREFIX, n);
+        entries.insert(label.clone(), Entry { target, built: false });
+        Ok(Reservation::Reserved(label))
+    }
+
+    /// Records that `label`'s window exists. A no-op if it was already removed
+    /// (a window destroyed the moment it appeared).
+    pub fn mark_built(&self, label: &str) {
+        if let Some(e) = self.lock().get_mut(label) {
+            e.built = true;
+        }
+    }
+
+    /// Points `label`'s entry at `container_path`, unless another window already
+    /// has that file open — then the entry is left alone, so no two entries are
+    /// ever resolved to the same file.
+    pub fn choose(
+        &self,
+        label: &str,
+        container_path: String,
+        is_live: impl Fn(&str) -> bool,
+    ) -> Result<Choice, String> {
+        let mut entries = self.lock();
+        prune(&mut entries, &is_live);
+        let project_id = entries
+            .get(label)
+            .ok_or_else(|| "This file window is no longer registered.".to_string())?
+            .target
+            .project_id
+            .clone();
+        if let Some((other, built)) = open_on(&entries, &project_id, &container_path, Some(label)) {
+            return Ok(Choice::AlreadyOpen { label: other, built });
+        }
+        let entry = entries.get_mut(label).expect("checked above under the same lock");
+        entry.target.state = ViewerTargetState::Resolved { container_path };
+        Ok(Choice::Resolved(entry.target.clone()))
+    }
+
+    pub fn get(&self, label: &str) -> Option<ViewerTarget> {
+        self.lock().get(label).map(|e| e.target.clone())
+    }
+
+    pub fn set_state(&self, label: &str, state: ViewerTargetState) -> Result<ViewerTarget, String> {
+        let mut entries = self.lock();
+        let entry = entries
+            .get_mut(label)
+            .ok_or_else(|| "This file window is no longer registered.".to_string())?;
+        entry.target.state = state;
+        Ok(entry.target.clone())
+    }
+
+    pub fn remove(&self, label: &str) {
+        self.lock().remove(label);
+    }
+
+    pub fn find_open(&self, project_id: &str, container_path: &str) -> Option<String> {
+        open_on(&self.lock(), project_id, container_path, None).map(|(label, _)| label)
+    }
+
+    pub fn len(&self) -> usize {
+        self.lock().len()
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn target(project: &str, path: &str) -> ViewerTarget {
+        ViewerTarget {
+            project_id: project.into(),
+            project_name: "Demo".into(),
+            raw_path: path.into(),
+            state: ViewerTargetState::Resolved { container_path: path.into() },
+            initial: Location { line: Some(3), col: None, end_line: None },
+        }
+    }
+
+    fn all_live(_: &str) -> bool {
+        true
+    }
+
+    /// Reserves a label that must be new.
+    fn fresh(r: &ViewerRegistry, t: ViewerTarget) -> String {
+        match r.reserve(t, all_live).unwrap() {
+            Reservation::Reserved(label) => label,
+            other => panic!("expected a new label, got {:?}", other),
+        }
+    }
+
+    fn choosing(project: &str, candidates: &[&str]) -> ViewerTarget {
+        ViewerTarget {
+            state: ViewerTargetState::Choose { candidates: candidates.iter().map(|c| c.to_string()).collect() },
+            ..target(project, "a")
+        }
+    }
+
+    #[test]
+    fn labels_are_sequential_and_never_reused() {
+        let r = ViewerRegistry::default();
+        let a = fresh(&r, target("p", "/workspace/a"));
+        let b = fresh(&r, target("p", "/workspace/b"));
+        assert_eq!(a, "file-viewer-1");
+        assert_eq!(b, "file-viewer-2");
+        r.remove(&a);
+        let c = fresh(&r, target("p", "/workspace/c"));
+        assert_eq!(c, "file-viewer-3");
+        assert_eq!(r.len(), 2);
+    }
+
+    #[test]
+    fn the_cap_refuses_the_twenty_first_window() {
+        let r = ViewerRegistry::default();
+        for i in 0..MAX_VIEWER_WINDOWS {
+            fresh(&r, target("p", &format!("/workspace/{}", i)));
+        }
+        let err = r.reserve(target("p", "/workspace/one-more"), all_live).unwrap_err();
+        assert!(err.contains("20"), "{}", err);
+        assert_eq!(r.len(), MAX_VIEWER_WINDOWS);
+    }
+
+    #[test]
+    fn an_open_resolved_file_is_found_by_project_and_path() {
+        let r = ViewerRegistry::default();
+        let label = fresh(&r, target("p", "/workspace/a"));
+        assert_eq!(r.find_open("p", "/workspace/a"), Some(label.clone()));
+        assert_eq!(r.find_open("other", "/workspace/a"), None);
+        // A window still choosing is not "open on" any path.
+        r.set_state(&label, ViewerTargetState::Choose { candidates: vec!["/workspace/a".into()] }).unwrap();
+        assert_eq!(r.find_open("p", "/workspace/a"), None);
+        r.remove(&label);
+        assert_eq!(r.get(&label), None);
+    }
+
+    #[test]
+    fn set_state_on_an_unknown_label_is_an_error() {
+        let r = ViewerRegistry::default();
+        assert!(r.set_state("file-viewer-9", ViewerTargetState::NotFound { tried: vec![] }).is_err());
+    }
+
+    #[test]
+    fn target_state_serialises_with_a_kind_tag() {
+        let s = serde_json::to_string(&ViewerTargetState::NotFound { tried: vec!["/x".into()] }).unwrap();
+        assert_eq!(s, r#"{"kind":"not_found","tried":["/x"]}"#);
+    }
+
+    /// I1: a second click while the first window is still being built must find
+    /// that window, not read it as stale and reserve a second one.
+    #[test]
+    fn a_window_being_built_is_found_not_replaced() {
+        let r = ViewerRegistry::default();
+        let a = fresh(&r, target("p", "/workspace/a"));
+        // No window exists yet for `a`: `is_live` says so, and it must not matter.
+        let second = r.reserve(target("p", "/workspace/a"), |_| false).unwrap();
+        assert_eq!(second, Reservation::Existing { label: a.clone(), built: false });
+        assert!(r.get(&a).is_some());
+        assert_eq!(r.len(), 1);
+
+        r.mark_built(&a);
+        let third = r.reserve(target("p", "/workspace/a"), all_live).unwrap();
+        assert_eq!(third, Reservation::Existing { label: a, built: true });
+        assert_eq!(r.len(), 1);
+    }
+
+    /// A built entry whose window is gone is stale: pruned, and the file reopens.
+    #[test]
+    fn a_built_entry_without_a_window_is_pruned_and_the_file_reopens() {
+        let r = ViewerRegistry::default();
+        let a = fresh(&r, target("p", "/workspace/a"));
+        r.mark_built(&a);
+        let again = r.reserve(target("p", "/workspace/a"), |_| false).unwrap();
+        assert_eq!(again, Reservation::Reserved("file-viewer-2".into()));
+        assert_eq!(r.get(&a), None);
+        assert_eq!(r.len(), 1);
+    }
+
+    /// M2: a leaked entry of any state cannot hold a cap slot once built and gone,
+    /// and an entry still being built always keeps its slot.
+    #[test]
+    fn leaked_entries_of_every_state_free_their_cap_slot() {
+        let r = ViewerRegistry::default();
+        let mut labels = Vec::new();
+        for i in 0..MAX_VIEWER_WINDOWS {
+            let t = match i % 3 {
+                0 => target("p", &format!("/workspace/{}", i)),
+                1 => choosing("p", &["/workspace/x", "/workspace/y"]),
+                _ => ViewerTarget { state: ViewerTargetState::NotFound { tried: vec![] }, ..target("p", "z") },
+            };
+            labels.push(fresh(&r, t));
+        }
+        // All still being built: none may be pruned, so the cap holds.
+        assert!(r.reserve(target("p", "/workspace/new"), |_| false).is_err());
+        for l in &labels {
+            r.mark_built(l);
+        }
+        // Built, and one of each state has lost its window.
+        let dead = [labels[0].clone(), labels[1].clone(), labels[2].clone()];
+        let live = |l: &str| !dead.iter().any(|d| d == l);
+        assert!(matches!(r.reserve(target("p", "/workspace/new"), live), Ok(Reservation::Reserved(_))));
+        assert_eq!(r.len(), MAX_VIEWER_WINDOWS - 2);
+        for d in &dead {
+            assert_eq!(r.get(d), None);
+        }
+    }
+
+    #[test]
+    fn mark_built_on_a_removed_label_is_a_no_op() {
+        let r = ViewerRegistry::default();
+        let a = fresh(&r, target("p", "/workspace/a"));
+        r.remove(&a);
+        r.mark_built(&a);
+        assert_eq!(r.get(&a), None);
+    }
+
+    /// M5: choosing a file another window already has leaves the chooser alone,
+    /// so two entries are never resolved to the same file.
+    #[test]
+    fn choosing_a_file_open_elsewhere_does_not_resolve_a_second_entry() {
+        let r = ViewerRegistry::default();
+        let open = fresh(&r, target("p", "/workspace/x"));
+        r.mark_built(&open);
+        let chooser = fresh(&r, choosing("p", &["/workspace/x", "/workspace/y"]));
+        r.mark_built(&chooser);
+
+        let c = r.choose(&chooser, "/workspace/x".into(), all_live).unwrap();
+        assert_eq!(c, Choice::AlreadyOpen { label: open.clone(), built: true });
+        assert!(matches!(r.get(&chooser).unwrap().state, ViewerTargetState::Choose { .. }));
+
+        match r.choose(&chooser, "/workspace/y".into(), all_live).unwrap() {
+            Choice::Resolved(t) => assert_eq!(t.state, ViewerTargetState::Resolved { container_path: "/workspace/y".into() }),
+            other => panic!("expected Resolved, got {:?}", other),
+        }
+        assert_eq!(r.find_open("p", "/workspace/y"), Some(chooser));
+    }
+
+    #[test]
+    fn choosing_the_same_path_in_another_project_is_not_a_duplicate() {
+        let r = ViewerRegistry::default();
+        fresh(&r, target("other", "/workspace/x"));
+        let chooser = fresh(&r, choosing("p", &["/workspace/x"]));
+        assert!(matches!(r.choose(&chooser, "/workspace/x".into(), all_live), Ok(Choice::Resolved(_))));
+    }
+
+    #[test]
+    fn choose_on_an_unknown_label_is_an_error() {
+        let r = ViewerRegistry::default();
+        assert!(r.choose("file-viewer-9", "/workspace/x".into(), all_live).is_err());
+    }
+}

app/src-tauri/src/file_viewer/resolve.rs

@@ -0,0 +1,166 @@
+//! Turning what Claude printed into a container path that exists.
+//!
+//! Relative paths are the common case (Claude prints project-relative paths). The
+//! terminal exec's cwd is `/workspace`, and each project path is mounted at
+//! `/workspace/<mount_name>`, so those are the roots probed, in that order. The probe
+//! is one exec as the container user and prints `realpath -e` of every candidate that
+//! is a regular file: `fetch_container_file` refuses a symlink, so the registry must
+//! hold the resolved path, not the one that was clicked.
+
+use crate::commands::file_commands::validate_container_path;
+use crate::docker::exec::exec_oneshot_streams_as;
+
+pub const MAX_CANDIDATES: usize = 16;
+const MAX_RAW_LEN: usize = 4096;
+
+/// `$@` are the candidates. For each regular file, print its resolved path.
+pub const PROBE_SCRIPT: &str = r#"for c in "$@"; do if test -f "$c"; then realpath -e -- "$c" 2>/dev/null; fi; done; exit 0"#;
+
+pub fn candidate_paths(raw: &str, mount_names: &[String]) -> Result<Vec<String>, String> {
+    if raw.is_empty() {
+        return Err("The path is empty.".into());
+    }
+    if raw.len() > MAX_RAW_LEN {
+        return Err("The path is too long.".into());
+    }
+    if raw.contains('\0') {
+        return Err("The path contains a NUL byte.".into());
+    }
+    if raw.split('/').any(|seg| seg == "..") {
+        return Err(format!("{} climbs out of its folder with `..`; refusing.", raw));
+    }
+
+    if raw.starts_with('/') {
+        let normalised = collapse(raw);
+        validate_container_path("File", &normalised)?;
+        return Ok(vec![normalised]);
+    }
+
+    let rel = collapse(raw.strip_prefix("./").unwrap_or(raw));
+    let rel = rel.trim_start_matches("./");
+    if rel.is_empty() {
+        return Err("The path is empty.".into());
+    }
+
+    let mut out: Vec<String> = Vec::new();
+    let mut push = |candidate: String| {
+        if out.len() < MAX_CANDIDATES && !out.contains(&candidate) {
+            out.push(candidate);
+        }
+    };
+    push(format!("/workspace/{}", rel));
+    for mount in mount_names {
+        if mount.is_empty() || mount.contains('/') || mount == "." || mount == ".." {
+            continue;
+        }
+        push(format!("/workspace/{}/{}", mount, rel));
+    }
+    for c in &out {
+        validate_container_path("File", c)?;
+    }
+    Ok(out)
+}
+
+/// `a//b/./c` → `a/b/c`. Never touches `..` (rejected before this runs).
+fn collapse(path: &str) -> String {
+    let absolute = path.starts_with('/');
+    let joined = path
+        .split('/')
+        .filter(|seg| !seg.is_empty() && *seg != ".")
+        .collect::<Vec<_>>()
+        .join("/");
+    if absolute { format!("/{}", joined) } else { joined }
+}
+
+/// One resolved path per line; anything that is not an absolute, valid container path is
+/// dropped (the script's own diagnostics go to stderr, but a hostile `realpath` output is
+/// still container-authored text).
+pub fn parse_probe_output(stdout: &str) -> Vec<String> {
+    let mut seen: Vec<String> = Vec::new();
+    for line in stdout.lines() {
+        let line = line.trim();
+        if line.is_empty() || validate_container_path("File", line).is_err() {
+            continue;
+        }
+        if !seen.iter().any(|s| s == line) {
+            seen.push(line.to_string());
+        }
+    }
+    seen
+}
+
+pub async fn probe_candidates(
+    container_id: &str,
+    candidates: &[String],
+) -> Result<Vec<String>, String> {
+    let mut cmd: Vec<String> = vec!["sh".into(), "-c".into(), PROBE_SCRIPT.into(), "probe".into()];
+    cmd.extend(candidates.iter().cloned());
+    let (stdout, _stderr, _code) =
+        exec_oneshot_streams_as(container_id, "claude", cmd, Vec::new()).await?;
+    Ok(parse_probe_output(&stdout))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn mounts(names: &[&str]) -> Vec<String> {
+        names.iter().map(|s| s.to_string()).collect()
+    }
+
+    #[test]
+    fn an_absolute_path_is_its_own_only_candidate() {
+        let c = candidate_paths("/workspace/api/src/main.rs", &mounts(&["api"])).unwrap();
+        assert_eq!(c, vec!["/workspace/api/src/main.rs"]);
+    }
+
+    #[test]
+    fn a_relative_path_probes_workspace_then_each_mount() {
+        let c = candidate_paths("src/main.rs", &mounts(&["api", "web"])).unwrap();
+        assert_eq!(
+            c,
+            vec!["/workspace/src/main.rs", "/workspace/api/src/main.rs", "/workspace/web/src/main.rs"]
+        );
+    }
+
+    #[test]
+    fn dot_prefix_and_duplicate_slashes_are_normalised_and_candidates_deduped() {
+        let c = candidate_paths("./src//main.rs", &mounts(&["api", "api", ""])).unwrap();
+        assert_eq!(c, vec!["/workspace/src/main.rs", "/workspace/api/src/main.rs"]);
+    }
+
+    #[test]
+    fn traversal_nul_and_oversize_are_refused() {
+        assert!(candidate_paths("../etc/passwd", &[]).is_err());
+        assert!(candidate_paths("src/../../x", &[]).is_err());
+        assert!(candidate_paths("/workspace/../etc/passwd", &[]).is_err());
+        assert!(candidate_paths("a\0b", &[]).is_err());
+        assert!(candidate_paths("", &[]).is_err());
+        assert!(candidate_paths(&"a".repeat(5000), &[]).is_err());
+    }
+
+    #[test]
+    fn candidate_list_is_capped() {
+        let many: Vec<String> = (0..40).map(|i| format!("m{}", i)).collect();
+        let c = candidate_paths("x.rs", &many).unwrap();
+        assert_eq!(c.len(), MAX_CANDIDATES);
+    }
+
+    #[test]
+    fn probe_output_keeps_valid_resolved_regular_files_only() {
+        let out = "/workspace/api/src/main.rs\n/workspace/api/src/main.rs\n\nrelative/junk\n/etc/../x\n/workspace/web/src/main.rs\n";
+        assert_eq!(
+            parse_probe_output(out),
+            vec!["/workspace/api/src/main.rs", "/workspace/web/src/main.rs"]
+        );
+    }
+
+    #[test]
+    fn the_probe_script_prints_resolved_paths_of_regular_files() {
+        // Shape assertions: the script is data handed to `sh -c`, and these are the
+        // three things a later edit must not lose.
+        assert!(PROBE_SCRIPT.contains("test -f"));
+        assert!(PROBE_SCRIPT.contains("realpath -e --"));
+        assert!(PROBE_SCRIPT.contains("for c in \"$@\""));
+    }
+}

app/src-tauri/src/file_viewer/window.rs

@@ -0,0 +1,27 @@
+//! The viewer window itself. Mirrors `browser_view/popout.rs`, with two differences:
+//! the URL is the app's own second entry (`WebviewUrl::App`), so the capability in
+//! `capabilities/file-viewer.json` applies; and the registry entry is removed on
+//! `Destroyed`, which fires for both the X button (after JS calls `destroy()`) and a
+//! Rust-side `destroy()`.
+
+use tauri::{AppHandle, Manager, WebviewUrl, WebviewWindowBuilder, WindowEvent};
+
+use super::registry::ViewerRegistry;
+
+pub fn open_viewer_window(app: &AppHandle, label: &str, title: &str) -> Result<(), String> {
+    let window = WebviewWindowBuilder::new(app, label, WebviewUrl::App("viewer.html".into()))
+        .title(title)
+        .inner_size(900.0, 700.0)
+        .min_inner_size(480.0, 320.0)
+        .build()
+        .map_err(|e| format!("Could not open the file window: {}", e))?;
+
+    let app_for_event = app.clone();
+    let label_owned = label.to_string();
+    window.on_window_event(move |event| {
+        if let WindowEvent::Destroyed = event {
+            app_for_event.state::<ViewerRegistry>().remove(&label_owned);
+        }
+    });
+    Ok(())
+}

app/src-tauri/src/file_viewer/write.rs

@@ -0,0 +1,604 @@
+//! Saving: stage in `/tmp`, then swap in as the container user.
+//!
+//! The Docker archive API writes as root, so it is used for exactly one thing — landing
+//! the payload at `/tmp/triple-c-viewer-<uuid>`, owned by the container user (the
+//! existing `write_file_to_container`). Everything that touches the *target directory*
+//! runs in an exec as `claude`, so a save can do nothing the user's own shell could not.
+//! A non-root process cannot `chown`, so the saved file is owned by the container user,
+//! as it would be after Claude Code edited it; mode is kept with `chmod --reference`.
+
+use serde::Serialize;
+use sha2::{Digest, Sha256};
+
+use crate::commands::file_commands::clip_container_text;
+use crate::docker::exec::{exec_oneshot_streams_as, ExecSessionManager};
+
+/// Spec §4/§5: only untruncated (≤ 1 MiB) text is editable, so nothing larger is saved.
+pub const MAX_WRITE_BYTES: usize = 1024 * 1024;
+
+pub fn sha256_hex(bytes: &[u8]) -> String {
+    let digest = Sha256::digest(bytes);
+    digest.iter().map(|b| format!("{:02x}", b)).collect()
+}
+
+pub fn is_sha256_hex(s: &str) -> bool {
+    s.len() == 64 && s.bytes().all(|b| matches!(b, b'0'..=b'9' | b'a'..=b'f'))
+}
+
+/// `$1` target, `$2` staged payload in /tmp, `$3` the hash the editor loaded from.
+/// Exit 1 = a step failed (unreadable target, a failed stage/replace, …), 3 = changed
+/// on disk, 4 = gone, 5 = the target is not writable by the container user; stdout on
+/// success is `sha256sum` of the target *after* the write. That is not necessarily the
+/// hash of what we wrote: another writer (Claude Code, on the same file) can land
+/// between `mv` and `sha256sum`. `saved_file` therefore takes the save's base from the
+/// bytes and only reports this one as what the disk held afterwards (M2).
+///
+/// P15: `sha256sum -- "$target"` prefixes its whole line with `\` when the path
+/// contains a backslash or a newline, so `$actual` has that prefix stripped before
+/// it is compared with `$expect` (which never carries one) — otherwise such a path
+/// would conflict forever.
+///
+/// I1: `$actual` is read from a plain `sha256sum` command substitution, not a
+/// pipeline into `cut` — POSIX sh has no `pipefail`, so `cmd | cut … || exit 1` tests
+/// only `cut`'s exit status and an unreadable file (EACCES, EIO) fell through as a
+/// false "changed on disk" conflict (empty `$actual` never equals `$expect`) instead
+/// of a real error, hiding the actual failure from the user and from `classify_write`.
+///
+/// I2/M3: `$staged` is created by `mktemp` (exclusive — never follows a planted
+/// symlink or stale leftover at that name) and is part of the `EXIT` trap from the
+/// moment it is assigned, so a failure at any later step (`cp`, `chmod`, `mv`) cannot
+/// leave a partial `.<name>.triple-c-<suffix>` behind in the user's own directory —
+/// including on a signal, for the steps after the trap covers it.
+pub const WRITE_SCRIPT: &str = r#"target=$1; tmp=$2; expect=$3
+staged=
+trap 'rm -f -- "$tmp" ${staged:+"$staged"}' EXIT
+test -f "$target" || exit 4
+actual=$(sha256sum -- "$target") || exit 1
+actual=${actual%% *}; actual=${actual#\\}
+[ "$actual" = "$expect" ] || exit 3
+# I3: the file's own mode is a boundary the user set from outside the container (0444,
+# a different owning uid, a read-only bind mount, …). Replacing it via rename or
+# truncating it in place would silently cross that boundary even though `claude` is
+# allowed to — an editor such as vim, or a plain `echo > file` in the user's own shell,
+# would refuse. This is stricter than spec §5 step 3's literal "if the directory is
+# writable" branch, which never looks at the file's own permissions; the branch below
+# only ever chooses *how* to write, never *whether*.
+#
+# The rename branch replaces whatever is at "$target" (a symlink planted there after
+# the window opened is replaced, not followed). The in-place `cat >` fallback, taken
+# only for a writable file in a read-only directory, DOES follow such a symlink and
+# writes through it. That is accepted: the write runs as `claude`, so it can reach
+# nothing Claude Code in the same container cannot already write.
+[ -w "$target" ] || { echo "The file is read-only for the container user." >&2; exit 5; }
+dir=$(dirname -- "$target"); name=$(basename -- "$target")
+if [ -w "$dir" ]; then
+  staged=$(mktemp -- "$dir/.$name.triple-c-XXXXXX") || exit 1
+  cp -- "$tmp" "$staged" || exit 1
+  chmod --reference="$target" "$staged" 2>/dev/null
+  mv -f -- "$staged" "$target" || exit 1
+else
+  cat -- "$tmp" > "$target" || exit 1
+fi
+sha256sum -- "$target""#;
+
+/// A save refused because the file changed since its base hash. The frontend matches
+/// this prefix; its copy lives in `app/src/viewer/ipcMessages.ts` (pinned by a test).
+pub const CONFLICT_PREFIX: &str = "conflict:";
+/// A save refused because the file no longer exists; mirrored in `ipcMessages.ts`.
+pub const GONE_PREFIX: &str = "gone:";
+/// The read-only refusal. The script echoes the same sentence (pinned by a test), but
+/// the caller always gets this constant, whatever the script printed; mirrored in
+/// `ipcMessages.ts`.
+pub const READ_ONLY_MESSAGE: &str = "The file is read-only for the container user.";
+
+/// I3: distinct from the generic failure code so the caller can hand back a specific,
+/// readable message instead of whatever the script's own diagnostic text says.
+const EXIT_READ_ONLY: i64 = 5;
+
+pub enum WriteOutcome {
+    Saved(String),
+    Conflict,
+    Gone,
+    Failed(String),
+}
+
+pub fn classify_write(code: i64, stdout: &str, stderr: &str) -> WriteOutcome {
+    match code {
+        3 => WriteOutcome::Conflict,
+        4 => WriteOutcome::Gone,
+        EXIT_READ_ONLY => WriteOutcome::Failed(READ_ONLY_MESSAGE.into()),
+        0 => match stdout
+            .split_whitespace()
+            .next()
+            .map(|h| h.trim_start_matches('\\'))
+            .filter(|h| is_sha256_hex(h))
+        {
+            Some(h) => WriteOutcome::Saved(h.to_string()),
+            None => WriteOutcome::Failed(
+                "The container did not report the saved file's hash.".into(),
+            ),
+        },
+        _ => WriteOutcome::Failed(clip_container_text(stderr)),
+    }
+}
+
+/// The write script's argv beyond `sh -c SCRIPT`: `$0=save`, `$1=target`, `$2=tmp`,
+/// `$3=base_hash` — pulled out pure so the argument shape has a unit test (P8).
+fn write_command(target: &str, tmp: &str, base_hash: &str) -> Vec<String> {
+    vec![
+        "sh".to_string(),
+        "-c".to_string(),
+        WRITE_SCRIPT.to_string(),
+        "save".to_string(),
+        target.to_string(),
+        tmp.to_string(),
+        base_hash.to_string(),
+    ]
+}
+
+/// Refuses a payload too large to be editable, or a malformed base hash, before
+/// anything is staged in the container (P8).
+fn check_write_input(len: usize, base_hash: &str) -> Result<(), String> {
+    if len > MAX_WRITE_BYTES {
+        return Err("Files over 1 MiB are read-only in the viewer.".into());
+    }
+    if !is_sha256_hex(base_hash) {
+        return Err("The editor's base hash is malformed; reload the file.".into());
+    }
+    Ok(())
+}
+
+/// What a successful save reports: `hash` is the new base, `sha256_hex` of the bytes
+/// we wrote; `disk_hash` is what the container hashed right after the swap. They differ
+/// only when another writer landed in between, and then the editor must show "Changed
+/// on disk" rather than adopt the other writer's hash as its base (M2).
+#[derive(Clone, Debug, Serialize, PartialEq, Eq)]
+pub struct SavedFile {
+    pub hash: String,
+    pub disk_hash: String,
+}
+
+/// `viewer_write_file`'s result, pure so the error-prefix contract has a unit test.
+fn saved_file(outcome: WriteOutcome, bytes: &[u8]) -> Result<SavedFile, String> {
+    match outcome {
+        WriteOutcome::Saved(disk_hash) => Ok(SavedFile { hash: sha256_hex(bytes), disk_hash }),
+        WriteOutcome::Conflict => Err(format!(
+            "{} the file changed on disk since it was loaded.",
+            CONFLICT_PREFIX
+        )),
+        WriteOutcome::Gone => Err(format!("{} the file no longer exists.", GONE_PREFIX)),
+        WriteOutcome::Failed(msg) => Err(format!("Could not save the file: {}", msg)),
+    }
+}
+
+pub async fn write_file(
+    container_id: &str,
+    exec_manager: &ExecSessionManager,
+    target: &str,
+    bytes: &[u8],
+    base_hash: &str,
+) -> Result<SavedFile, String> {
+    check_write_input(bytes.len(), base_hash)?;
+    let tmp_name = format!("triple-c-viewer-{}", uuid::Uuid::new_v4().simple());
+    let tmp_path = exec_manager
+        .write_file_to_container(container_id, &tmp_name, bytes)
+        .await?;
+    let cmd = write_command(target, &tmp_path, base_hash);
+    let (stdout, stderr, code) =
+        exec_oneshot_streams_as(container_id, "claude", cmd, Vec::new()).await?;
+    saved_file(classify_write(code, &stdout, &stderr), bytes)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn sha256_matches_coreutils() {
+        // `printf 'hello\n' | sha256sum`
+        assert_eq!(
+            sha256_hex(b"hello\n"),
+            "5891b5b522d5df086d0ff0b110fbd9d21bb4fc7163af34d08286a2e846f6be03"
+        );
+        assert!(is_sha256_hex(&sha256_hex(b"")));
+        assert!(!is_sha256_hex("ABC"));
+        assert!(!is_sha256_hex(&"g".repeat(64)));
+    }
+
+    #[test]
+    fn exit_codes_map_to_outcomes() {
+        let h = "5891b5b522d5df086d0ff0b110fbd9d21bb4fc7163af34d08286a2e846f6be03";
+        assert!(matches!(classify_write(0, &format!("{}  /x\n", h), ""), WriteOutcome::Saved(s) if s == h));
+        assert!(matches!(classify_write(3, "", ""), WriteOutcome::Conflict));
+        assert!(matches!(classify_write(4, "", ""), WriteOutcome::Gone));
+        assert!(matches!(classify_write(1, "", "cp: Permission denied"), WriteOutcome::Failed(m) if m.contains("Permission denied")));
+        // Success without a parseable hash is still a failure: the editor's base would be wrong.
+        assert!(matches!(classify_write(0, "junk", ""), WriteOutcome::Failed(_)));
+    }
+
+    /// I3: exit 5 is the script's read-only refusal, and it must not be swallowed by
+    /// the generic `_ => Failed(stderr)` arm — the caller gets a fixed, readable
+    /// message regardless of exactly what the script printed.
+    #[test]
+    fn exit_five_is_a_distinct_read_only_refusal() {
+        assert!(matches!(
+            classify_write(5, "", "The file is read-only for the container user."),
+            WriteOutcome::Failed(m) if m.contains("read-only")
+        ));
+    }
+
+    /// M2: the new base is the hash of the bytes we wrote, never the script's
+    /// post-`mv` hash, which may belong to a writer that landed after us.
+    #[test]
+    fn a_save_takes_its_base_from_the_written_bytes() {
+        let ours = sha256_hex(b"new\n");
+        let same = saved_file(WriteOutcome::Saved(ours.clone()), b"new\n").unwrap();
+        assert_eq!(same, SavedFile { hash: ours.clone(), disk_hash: ours.clone() });
+
+        let foreign = sha256_hex(b"someone else's\n");
+        let raced = saved_file(WriteOutcome::Saved(foreign.clone()), b"new\n").unwrap();
+        assert_eq!(raced.hash, ours, "the base must be what we wrote");
+        assert_eq!(raced.disk_hash, foreign, "the foreign hash is reported, not adopted");
+    }
+
+    /// Important #4: the frontend matches these exact strings
+    /// (`app/src/viewer/ipcMessages.ts`), so pin them here too.
+    #[test]
+    fn save_errors_keep_the_prefix_contract() {
+        let conflict = saved_file(WriteOutcome::Conflict, b"").unwrap_err();
+        assert!(conflict.starts_with("conflict:"), "{conflict}");
+        assert_eq!(conflict, "conflict: the file changed on disk since it was loaded.");
+
+        let gone = saved_file(WriteOutcome::Gone, b"").unwrap_err();
+        assert!(gone.starts_with("gone:"), "{gone}");
+        assert_eq!(gone, "gone: the file no longer exists.");
+
+        let read_only = saved_file(classify_write(5, "", "whatever the script said"), b"").unwrap_err();
+        assert_eq!(read_only, "Could not save the file: The file is read-only for the container user.");
+        assert!(!read_only.starts_with(CONFLICT_PREFIX) && !read_only.starts_with(GONE_PREFIX));
+
+        let other = saved_file(classify_write(1, "", "No space left on device"), b"").unwrap_err();
+        assert_eq!(other, "Could not save the file: No space left on device");
+
+        // The script's own refusal text is the same sentence the caller is given.
+        assert!(WRITE_SCRIPT.contains(&format!("echo \"{}\" >&2; exit 5", READ_ONLY_MESSAGE)));
+    }
+
+    /// The TypeScript side keeps one copy of each matched string; a change on either
+    /// side without the other fails here.
+    #[test]
+    fn the_frontend_copies_of_the_ipc_messages_match() {
+        let path = std::path::Path::new(env!("CARGO_MANIFEST_DIR")).join("../src/viewer/ipcMessages.ts");
+        let ts = std::fs::read_to_string(&path).expect("app/src/viewer/ipcMessages.ts");
+        for (name, value) in [
+            ("CONFLICT_PREFIX", CONFLICT_PREFIX),
+            ("GONE_PREFIX", GONE_PREFIX),
+            ("READ_ONLY_MESSAGE", READ_ONLY_MESSAGE),
+            ("NOT_RUNNING_PREFIX", crate::commands::file_commands::NOT_RUNNING_PREFIX),
+        ] {
+            let line = format!("export const {} = \"{}\";", name, value);
+            assert!(ts.contains(&line), "ipcMessages.ts must contain `{line}`");
+        }
+    }
+
+    /// P15: a target path with a backslash makes `sha256sum` prefix the line;
+    /// the parsed hash must still be recognised as the saved hash.
+    #[test]
+    fn a_backslash_prefixed_saved_hash_is_still_recognised() {
+        let h = "5891b5b522d5df086d0ff0b110fbd9d21bb4fc7163af34d08286a2e846f6be03";
+        assert!(matches!(
+            classify_write(0, &format!("\\{}  /x\\y\n", h), ""),
+            WriteOutcome::Saved(s) if s == h
+        ));
+    }
+
+    #[test]
+    fn the_write_script_checks_then_swaps_and_always_cleans_up() {
+        for needle in [
+            "test -f \"$target\" || exit 4",
+            "exit 3",
+            "chmod --reference=\"$target\"",
+            "mv -f --",
+            "cat -- \"$tmp\" > \"$target\"",
+            // I2/M3: the trap covers the staged file too, and it comes from `mktemp`.
+            "trap 'rm -f -- \"$tmp\" ${staged:+\"$staged\"}' EXIT",
+            "mktemp -- \"$dir/.$name.triple-c-XXXXXX\"",
+            // I1: a plain command substitution, not a pipeline `cut` could mask.
+            "actual=$(sha256sum -- \"$target\") || exit 1",
+            // I3: a read-only target is refused before any write is attempted.
+            "[ -w \"$target\" ] || { echo \"The file is read-only for the container user.\" >&2; exit 5; }",
+        ] {
+            assert!(WRITE_SCRIPT.contains(needle), "missing: {}", needle);
+        }
+        // The old pipeline form must be gone, not merely superseded.
+        assert!(!WRITE_SCRIPT.contains("cut -d' ' -f1"));
+    }
+
+    /// P8: the write script's test list is binding, and the argument order is
+    /// exactly what a later edit could silently break.
+    #[test]
+    fn write_command_has_the_expected_argv_shape() {
+        let cmd = write_command("/w/t.txt", "/tmp/x", "abc123");
+        assert_eq!(
+            cmd,
+            vec![
+                "sh".to_string(),
+                "-c".to_string(),
+                WRITE_SCRIPT.to_string(),
+                "save".to_string(),
+                "/w/t.txt".to_string(),
+                "/tmp/x".to_string(),
+                "abc123".to_string(),
+            ]
+        );
+    }
+
+    /// P8: the size cap and base-hash checks are unit-testable in isolation from
+    /// the async `write_file`.
+    #[test]
+    fn check_write_input_refuses_oversized_payload_and_malformed_hash() {
+        let h = "5891b5b522d5df086d0ff0b110fbd9d21bb4fc7163af34d08286a2e846f6be03";
+        assert!(check_write_input(MAX_WRITE_BYTES, h).is_ok());
+        assert!(check_write_input(MAX_WRITE_BYTES + 1, h).is_err());
+        assert!(check_write_input(0, "not-a-hash").is_err());
+    }
+
+    // ── M10: WRITE_SCRIPT run for real, against a temp dir on the host ──────────
+    //
+    // The needle test above only proves the script *contains* certain substrings; it
+    // cannot catch the pipefail-shaped bug I1 was (the needle text was correct, the
+    // shell semantics were not). These run the exact `sh -c SCRIPT save target tmp
+    // hash` invocation `write_command` builds, so they pin the exit codes and cleanup
+    // behaviour that `write_file`/`classify_write` actually depend on. `sh` and the
+    // coreutils used here (`sha256sum`, `mktemp`, `dirname`, `basename`) are present
+    // on dev machines and CI alike.
+
+    #[cfg(unix)]
+    fn run_write_script(
+        target: &std::path::Path,
+        tmp: &std::path::Path,
+        base_hash: &str,
+    ) -> (i32, String, String) {
+        let out = std::process::Command::new("sh")
+            .arg("-c")
+            .arg(WRITE_SCRIPT)
+            .arg("save")
+            .arg(target)
+            .arg(tmp)
+            .arg(base_hash)
+            .output()
+            .expect("sh must be on PATH to run this test");
+        (
+            out.status.code().unwrap_or(-1),
+            String::from_utf8_lossy(&out.stdout).into_owned(),
+            String::from_utf8_lossy(&out.stderr).into_owned(),
+        )
+    }
+
+    #[cfg(unix)]
+    fn unique_test_dir(name: &str) -> std::path::PathBuf {
+        let dir = std::env::temp_dir().join(format!("tc-write-{}-{}", name, uuid::Uuid::new_v4()));
+        std::fs::create_dir_all(&dir).unwrap();
+        dir
+    }
+
+    #[cfg(unix)]
+    #[test]
+    fn on_the_host_a_clean_save_replaces_the_file_and_cleans_up() {
+        let dir = unique_test_dir("clean");
+        let target = dir.join("t.txt");
+        let tmp = dir.join("payload");
+        std::fs::write(&target, b"old\n").unwrap();
+        std::fs::write(&tmp, b"new\n").unwrap();
+        let base = sha256_hex(b"old\n");
+
+        let (code, stdout, stderr) = run_write_script(&target, &tmp, &base);
+
+        assert_eq!(code, 0, "stdout={stdout} stderr={stderr}");
+        let new_hash = sha256_hex(b"new\n");
+        assert!(stdout.contains(&new_hash), "stdout={stdout}");
+        // With no other writer, the reported disk hash is ours, so no conflict is shown.
+        let saved = saved_file(classify_write(code as i64, &stdout, &stderr), b"new\n").unwrap();
+        assert_eq!(saved, SavedFile { hash: new_hash.clone(), disk_hash: new_hash.clone() });
+        assert_eq!(std::fs::read(&target).unwrap(), b"new\n");
+        assert!(!tmp.exists(), "the staged /tmp payload must be cleaned up");
+
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    /// M2, for real: another writer lands between the script's `mv` and its final
+    /// `sha256sum` (simulated by a `sha256sum` shim on PATH that rewrites the target on
+    /// its second call). The save's base must still be the hash of our bytes, and the
+    /// foreign hash must come back as `disk_hash`, so the editor shows "Changed on disk".
+    #[cfg(unix)]
+    #[test]
+    fn on_the_host_a_write_that_lands_after_ours_is_reported_not_adopted() {
+        use std::os::unix::fs::PermissionsExt;
+        let real = std::process::Command::new("sh")
+            .args(["-c", "command -v sha256sum"])
+            .output()
+            .expect("sh");
+        let real = String::from_utf8_lossy(&real.stdout).trim().to_string();
+        assert!(!real.is_empty(), "sha256sum must be on PATH");
+
+        let dir = unique_test_dir("race");
+        let bin = dir.join("bin");
+        std::fs::create_dir_all(&bin).unwrap();
+        let mark = dir.join("called-once");
+        let shim = bin.join("sha256sum");
+        std::fs::write(
+            &shim,
+            format!(
+                "#!/bin/sh\nif [ -e '{mark}' ]; then printf 'theirs\\n' > \"$2\"; fi\n: > '{mark}'\nexec '{real}' \"$@\"\n",
+                mark = mark.display(),
+                real = real
+            ),
+        )
+        .unwrap();
+        std::fs::set_permissions(&shim, std::fs::Permissions::from_mode(0o755)).unwrap();
+
+        let target = dir.join("t.txt");
+        let tmp = dir.join("payload");
+        std::fs::write(&target, b"old\n").unwrap();
+        std::fs::write(&tmp, b"new\n").unwrap();
+        let path = format!("{}:{}", bin.display(), std::env::var("PATH").unwrap_or_default());
+        let out = std::process::Command::new("sh")
+            .env("PATH", path)
+            .arg("-c")
+            .arg(WRITE_SCRIPT)
+            .arg("save")
+            .arg(&target)
+            .arg(&tmp)
+            .arg(sha256_hex(b"old\n"))
+            .output()
+            .unwrap();
+        let (stdout, stderr) = (String::from_utf8_lossy(&out.stdout), String::from_utf8_lossy(&out.stderr));
+        assert_eq!(out.status.code(), Some(0), "stdout={stdout} stderr={stderr}");
+        assert_eq!(std::fs::read(&target).unwrap(), b"theirs\n", "the shim's write landed last");
+
+        let saved = saved_file(classify_write(0, &stdout, &stderr), b"new\n").unwrap();
+        assert_eq!(saved.hash, sha256_hex(b"new\n"));
+        assert_eq!(saved.disk_hash, sha256_hex(b"theirs\n"));
+
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    #[cfg(unix)]
+    #[test]
+    fn on_the_host_a_stale_base_hash_conflicts_and_leaves_everything_untouched() {
+        let dir = unique_test_dir("stale");
+        let target = dir.join("t.txt");
+        let tmp = dir.join("payload");
+        std::fs::write(&target, b"old\n").unwrap();
+        std::fs::write(&tmp, b"new\n").unwrap();
+        let wrong_base = sha256_hex(b"not what is on disk\n");
+
+        let (code, _stdout, stderr) = run_write_script(&target, &tmp, &wrong_base);
+
+        assert_eq!(code, 3, "stderr={stderr}");
+        assert_eq!(std::fs::read(&target).unwrap(), b"old\n", "must be untouched");
+        assert!(!tmp.exists(), "the staged /tmp payload must still be cleaned up");
+
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    #[cfg(unix)]
+    #[test]
+    fn on_the_host_a_missing_target_reports_gone() {
+        let dir = unique_test_dir("gone");
+        let target = dir.join("does-not-exist");
+        let tmp = dir.join("payload");
+        std::fs::write(&tmp, b"new\n").unwrap();
+
+        let (code, _stdout, stderr) = run_write_script(&target, &tmp, &sha256_hex(b"whatever"));
+
+        assert_eq!(code, 4, "stderr={stderr}");
+
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    /// I1: a real read failure must be a real error (exit 1), never the exit-3
+    /// conflict a bare `sha256sum | cut` pipeline (no `pipefail` in POSIX sh) would
+    /// silently produce.
+    #[cfg(unix)]
+    #[test]
+    fn on_the_host_an_unreadable_target_is_an_error_not_a_conflict() {
+        use std::os::unix::fs::PermissionsExt;
+        let dir = unique_test_dir("unreadable");
+        let target = dir.join("t.txt");
+        let tmp = dir.join("payload");
+        std::fs::write(&target, b"old\n").unwrap();
+        std::fs::write(&tmp, b"new\n").unwrap();
+        std::fs::set_permissions(&target, std::fs::Permissions::from_mode(0o000)).unwrap();
+
+        if std::fs::read(&target).is_ok() {
+            // Running as root (or some other bypass): 0o000 does not block reads,
+            // so this scenario cannot be reproduced here.
+            eprintln!("skipping: still able to read a 0o000 file (root?)");
+            let _ = std::fs::set_permissions(&target, std::fs::Permissions::from_mode(0o644));
+            let _ = std::fs::remove_dir_all(&dir);
+            return;
+        }
+
+        let (code, _stdout, stderr) = run_write_script(&target, &tmp, &sha256_hex(b"old\n"));
+
+        assert_eq!(
+            code, 1,
+            "an unreadable target must be a real error, not exit 3; stderr={stderr}"
+        );
+        assert!(!tmp.exists(), "the staged /tmp payload must still be cleaned up");
+
+        let _ = std::fs::set_permissions(&target, std::fs::Permissions::from_mode(0o644));
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    /// I3: a target the container user cannot write is refused outright, never
+    /// replaced via rename.
+    #[cfg(unix)]
+    #[test]
+    fn on_the_host_a_read_only_target_is_refused_not_replaced() {
+        use std::os::unix::fs::PermissionsExt;
+        let dir = unique_test_dir("readonly");
+        let target = dir.join("t.txt");
+        let tmp = dir.join("payload");
+        std::fs::write(&target, b"old\n").unwrap();
+        std::fs::write(&tmp, b"new\n").unwrap();
+        std::fs::set_permissions(&target, std::fs::Permissions::from_mode(0o444)).unwrap();
+
+        if std::fs::OpenOptions::new().write(true).open(&target).is_ok() {
+            eprintln!("skipping: still able to write a 0o444 file (root?)");
+            let _ = std::fs::set_permissions(&target, std::fs::Permissions::from_mode(0o644));
+            let _ = std::fs::remove_dir_all(&dir);
+            return;
+        }
+
+        let (code, _stdout, stderr) = run_write_script(&target, &tmp, &sha256_hex(b"old\n"));
+
+        assert_eq!(code as i64, EXIT_READ_ONLY, "stderr={stderr}");
+        assert!(stderr.contains("read-only"), "stderr={stderr}");
+        assert_eq!(
+            std::fs::read(&target).unwrap(),
+            b"old\n",
+            "a read-only file must not be replaced"
+        );
+        assert!(!tmp.exists(), "the staged /tmp payload must still be cleaned up");
+
+        let _ = std::fs::set_permissions(&target, std::fs::Permissions::from_mode(0o644));
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    /// I2: a failed stage (here: an unreadable source payload, so `cp` fails after
+    /// `mktemp` has already created the destination) must not leave a partial
+    /// `.<name>.triple-c-<suffix>` behind in the user's own directory.
+    #[cfg(unix)]
+    #[test]
+    fn on_the_host_a_failed_stage_leaves_no_partial_file_behind() {
+        use std::os::unix::fs::PermissionsExt;
+        let dir = unique_test_dir("cpfail");
+        let target = dir.join("t.txt");
+        let tmp = dir.join("payload");
+        std::fs::write(&target, b"old\n").unwrap();
+        std::fs::write(&tmp, b"new\n").unwrap();
+        std::fs::set_permissions(&tmp, std::fs::Permissions::from_mode(0o000)).unwrap();
+
+        if std::fs::read(&tmp).is_ok() {
+            eprintln!("skipping: still able to read a 0o000 file (root?)");
+            let _ = std::fs::remove_dir_all(&dir);
+            return;
+        }
+
+        let (code, _stdout, stderr) = run_write_script(&target, &tmp, &sha256_hex(b"old\n"));
+
+        assert_eq!(code, 1, "stderr={stderr}");
+        assert_eq!(std::fs::read(&target).unwrap(), b"old\n", "must be untouched");
+        let leftovers: Vec<_> = std::fs::read_dir(&dir)
+            .unwrap()
+            .filter_map(|e| e.ok())
+            .map(|e| e.file_name().to_string_lossy().into_owned())
+            .filter(|n| n.starts_with(".t.txt.triple-c-"))
+            .collect();
+        assert!(leftovers.is_empty(), "staged file(s) left behind: {leftovers:?}");
+
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+}

app/src-tauri/src/lib.rs

@@ -1,12 +1,16 @@
 mod auth_bridge;
 mod browser_view;
+#[cfg(test)]
+mod command_census;
 mod commands;
 mod docker;
+pub mod file_viewer;
 mod install_helper;
 mod logging;
 mod models;
 mod project_lock;
 mod storage;
+pub mod url_open;
 pub mod web_terminal;
 
 use std::sync::atomic::{AtomicBool, Ordering};
@@ -29,6 +33,21 @@ pub struct AppState {
     pub auth_bridge: Arc<AuthBridgeManager>,
     pub web_terminal_server: Arc<tokio::sync::Mutex<Option<WebTerminalServer>>>,
     pub lifecycle: Arc<Lifecycle>,
+    /// The file `preview_settings_import` last decrypted successfully, held
+    /// so `apply_settings_import` can re-read and re-decrypt the same file
+    /// without the frontend ever passing a host path back to Rust as an
+    /// argument — see the doc comment on `commands::settings_export_commands`
+    /// for why that direction specifically is the one this app treats as
+    /// dangerous. Deliberately re-decrypted rather than cached in plaintext:
+    /// nothing here holds a decrypted secret in memory for longer than one
+    /// command's execution.
+    ///
+    /// Also pins a hash of the file's ciphertext at preview time, so
+    /// `apply_settings_import` can refuse to proceed if the file on disk
+    /// changed underneath the pending import — otherwise confirming a
+    /// preview is not actually binding on what gets applied.
+    pub pending_settings_import:
+        Arc<tokio::sync::Mutex<Option<commands::settings_export_commands::PendingSettingsImport>>>,
 }
 
 // ─────────────────────────────────────────────────────────────────────────────
@@ -222,7 +241,9 @@ pub fn run() {
             auth_bridge,
             web_terminal_server: Arc::new(tokio::sync::Mutex::new(None)),
             lifecycle,
+            pending_settings_import: Arc::new(tokio::sync::Mutex::new(None)),
         })
+        .manage(file_viewer::registry::ViewerRegistry::default())
         .setup(move |app| {
             match tauri::image::Image::from_bytes(include_bytes!("../icons/icon.png")) {
                 Ok(icon) => {
@@ -247,16 +268,34 @@ pub fn run() {
             // logged warning rather than a failed start.
             //
             // Ordering matters. Probes are removed first because a probe holds
-            // an image open and the sweep will not force; pins are untagged
+            // an image open and the sweep will not force — both the probe
+            // containers and the probe images, the latter being the one orphan
+            // the sweep can never reach on its own; pins are untagged
             // second so the images they were holding are dangling by the time
             // the sweep lists them; the sweep runs last and collects both.
+            let projects_store_for_cleanup = projects_store_setup.clone();
             tauri::async_runtime::spawn(async move {
                 crate::docker::reap_probe_containers().await;
+                // Probe *images* too, and for a sharper reason: a probe
+                // container merely pins an image the sweep then refuses to
+                // touch, whereas a leftover probe image is tagged and so
+                // nothing else in this app can ever collect it. See
+                // `reap_probe_images`.
+                crate::docker::reap_probe_images().await;
                 let reaped = crate::docker::reap_stale_migration_pins().await;
                 if reaped > 0 {
                     log::info!("Startup housekeeping dropped {} stale rollback pin(s)", reaped);
                 }
                 crate::docker::sweep_orphaned_snapshots_logged("startup").await;
+                // A container/image/volume `remove_project` could not delete
+                // is recorded rather than lost — see triple-c#31 — and this is
+                // the only place anything ever retries it. Takes the store so
+                // it can refuse to touch a project that turns out to still be
+                // live — see the long comment on the function itself.
+                crate::commands::project_commands::retry_pending_cleanup_logged(
+                    &projects_store_for_cleanup,
+                )
+                .await;
             });
 
             // Auto-start web terminal server if enabled in settings
@@ -435,7 +474,6 @@ pub fn run() {
             commands::docker_commands::check_image_exists,
             commands::docker_commands::build_image,
             commands::docker_commands::get_container_info,
-            commands::docker_commands::list_sibling_containers,
             // Projects
             commands::project_commands::list_projects,
             commands::project_commands::add_project,
@@ -445,6 +483,10 @@ pub fn run() {
             commands::project_commands::stop_project_container,
             commands::project_commands::rebuild_project_container,
             commands::project_commands::reconcile_project_statuses,
+            // Notes
+            commands::notes_commands::list_notes,
+            commands::notes_commands::save_note,
+            commands::notes_commands::delete_note,
             // Container base-image migration
             commands::migration_commands::get_container_staleness,
             commands::migration_commands::migrate_project_to_base,
@@ -485,6 +527,10 @@ pub fn run() {
             commands::settings_commands::inspect_ca_cert_path,
             commands::settings_commands::list_aws_profiles,
             commands::settings_commands::detect_host_timezone,
+            // Settings export/import
+            commands::settings_export_commands::export_settings,
+            commands::settings_export_commands::preview_settings_import,
+            commands::settings_export_commands::apply_settings_import,
             // Terminal
             commands::terminal_commands::open_terminal_session,
             commands::terminal_commands::terminal_input,
@@ -497,12 +543,19 @@ pub fn run() {
             commands::terminal_commands::stop_audio_bridge,
             // Files
             commands::file_commands::list_container_files,
-            commands::file_commands::download_container_file,
             commands::file_commands::download_container_backup,
-            commands::file_commands::upload_file_to_container,
+            commands::file_commands::download_container_file,
+            commands::file_commands::upload_files_to_container,
             commands::file_commands::read_container_file,
             commands::file_commands::rename_container_path,
             commands::file_commands::create_container_directory,
+            // Terminal file viewer
+            commands::file_viewer_commands::open_file_viewer,
+            commands::file_viewer_commands::viewer_get_state,
+            commands::file_viewer_commands::viewer_choose_file,
+            commands::file_viewer_commands::viewer_read_file,
+            commands::file_viewer_commands::viewer_poll_file,
+            commands::file_viewer_commands::viewer_write_file,
             // AWS
             commands::aws_commands::aws_sso_refresh,
             // Updates
@@ -511,6 +564,9 @@ pub fn run() {
             commands::update_commands::check_image_update,
             // Help
             commands::help_commands::get_help_content,
+            // Opening a link in the host browser (see `url_open` for why this
+            // is not `@tauri-apps/plugin-opener` on Linux)
+            url_open::open_url_external,
             // Install helper
             commands::install_helper_commands::detect_install_options,
             commands::install_helper_commands::run_docker_install,
@@ -689,6 +745,154 @@ mod tests {
     /// pulls in `core:image:default` → `allow-from-path`, which is an
     /// unconditional `std::fs::read` of any host path with no scope check, and
     /// nothing in the frontend has ever imported `@tauri-apps/api/image`.
+    /// Every `#[tauri::command]` is registered, and every registration names a
+    /// command that exists.
+    ///
+    /// This is the shape of the bug that caused the original OAuth-callback
+    /// complaint: `set_auth_bridge_enabled` existed, worked, and had a typed
+    /// frontend wrapper — with **zero call sites**. The switch the docs told
+    /// users to flip was never wired to anything, so the bridge stayed off and
+    /// every login callback was refused. Nothing failed; the feature was simply
+    /// absent, and no test noticed because both halves compiled.
+    ///
+    /// The reverse direction matters too, and for a sharper reason: a command
+    /// that is registered but reachable from nowhere is still IPC surface a
+    /// compromised webview can call. `list_sibling_containers` — which returned
+    /// every container on the daemon, including the user's unrelated work —
+    /// sat in exactly that state, and this test is what found it. It has since
+    /// been removed at all four levels: registration, command, docker helper,
+    /// and the frontend wrapper and type.
+    ///
+    /// So this asserts the two lists agree, and leaves *deciding* what belongs
+    /// on them to a human. It cannot see frontend call sites; `tsc` and the
+    /// vitest suite cover that side.
+    #[test]
+    fn every_command_is_registered_exactly_once() {
+        use std::collections::BTreeSet;
+
+        let mut defined: BTreeSet<String> = BTreeSet::new();
+
+        // Walk the source tree for the command attribute and take the `fn` name
+        // that follows.
+        //
+        // The first version of this matched `line.trim() == "#[tauri::command]"`
+        // exactly and broke on the first non-`#` line. An audit got five real,
+        // compiling, unregistered commands past it — `#[tauri::command(async)]`,
+        // `#[tauri::command(rename_all = "snake_case")]`, a trailing comment,
+        // spaces in the path, and a bare `#[command]` after `use tauri::command`
+        // — plus `pub(crate) fn` and a `///` line between attribute and `fn`.
+        // Every one of those is a command the frontend could not call, which is
+        // the bug this test exists for, and the test stayed green.
+        //
+        // The asymmetry matters: confusion on the *definition* side is a silent
+        // pass, while on the *registration* side it fails loudly against
+        // legitimate code — and rustc already covers that direction. So this
+        // errs toward over-matching definitions.
+        fn collect(dir: &std::path::Path, out: &mut BTreeSet<String>) {
+            let Ok(entries) = std::fs::read_dir(dir) else { return };
+            for entry in entries.flatten() {
+                let path = entry.path();
+                if path.is_dir() {
+                    collect(&path, out);
+                } else if path.extension().is_some_and(|e| e == "rs") {
+                    let Ok(text) = std::fs::read_to_string(&path) else { continue };
+                    let lines: Vec<&str> = text.lines().collect();
+                    for (i, line) in lines.iter().enumerate() {
+                        let t = line.trim();
+                        // `#[tauri::command]`, `#[tauri::command(async)]`,
+                        // `#[tauri :: command]`, a bare `#[command]` under
+                        // `use tauri::command`, and any of those with a
+                        // trailing comment.
+                        let attr = t.strip_prefix("#[").map(|a| {
+                            a.split(']').next().unwrap_or("").replace(' ', "")
+                        });
+                        let is_command_attr = attr.is_some_and(|a| {
+                            a == "command" || a == "tauri::command"
+                                || a.starts_with("command(")
+                                || a.starts_with("tauri::command(")
+                        });
+                        if !is_command_attr {
+                            continue;
+                        }
+                        // Skip further attributes and doc comments rather than
+                        // giving up at the first line that is not an attribute.
+                        for next in lines.iter().skip(i + 1) {
+                            let t = next.trim();
+                            if t.starts_with('#') || t.starts_with("//") || t.is_empty() {
+                                continue;
+                            }
+                            // Any visibility, then `fn` or `async fn`.
+                            let after_vis = t
+                                .strip_prefix("pub(crate) ")
+                                .or_else(|| t.strip_prefix("pub(super) "))
+                                .or_else(|| t.strip_prefix("pub(in crate) "))
+                                .or_else(|| t.strip_prefix("pub "))
+                                .unwrap_or(t);
+                            let after_async =
+                                after_vis.strip_prefix("async ").unwrap_or(after_vis);
+                            if let Some(rest) = after_async.strip_prefix("fn ") {
+                                if let Some(name) = rest.split(['(', '<']).next() {
+                                    out.insert(name.trim().to_string());
+                                }
+                            }
+                            break;
+                        }
+                    }
+                }
+            }
+        }
+        collect(
+            std::path::Path::new(concat!(env!("CARGO_MANIFEST_DIR"), "/src")),
+            &mut defined,
+        );
+
+        // The registration list, read from this file by the same parser `build.rs` uses to
+        // declare the AppManifest — so if this test can see a command, the ACL can too.
+        let ordered = crate::command_census::registered_commands(include_str!("lib.rs"))
+            .expect("lib.rs should contain a generate_handler! list");
+        let registered: BTreeSet<String> = ordered.iter().cloned().collect();
+
+        assert!(
+            !defined.is_empty() && !registered.is_empty(),
+            "the scan found nothing — it has stopped testing anything (defined={}, registered={})",
+            defined.len(),
+            registered.len()
+        );
+
+        let unregistered: Vec<&String> = defined.difference(&registered).collect();
+        assert!(
+            unregistered.is_empty(),
+            "these commands exist but are not registered, so the frontend cannot call them: {:?}",
+            unregistered
+        );
+
+        let undefined: Vec<&String> = registered.difference(&defined).collect();
+        assert!(
+            undefined.is_empty(),
+            "these are registered but no `#[tauri::command]` defines them: {:?}",
+            undefined
+        );
+
+        // "exactly once" was in this test's name and not in its body: both
+        // sides were sets, so registering the same command twice in a
+        // hand-maintained 118-line list compiled, warned about nothing, and
+        // passed here.
+        let mut seen: Vec<&str> = Vec::new();
+        let mut duplicated: Vec<&str> = Vec::new();
+        for name in &ordered {
+            if seen.contains(&name.as_str()) {
+                duplicated.push(name);
+            } else {
+                seen.push(name);
+            }
+        }
+        assert!(
+            duplicated.is_empty(),
+            "these are registered more than once: {:?}",
+            duplicated
+        );
+    }
+
     #[test]
     fn the_capability_grants_are_the_ones_that_were_reviewed() {
         let raw = include_str!("../capabilities/default.json");
@@ -708,7 +912,10 @@ mod tests {
             })
             .collect();
 
-        let mut sorted = listed.clone();
+        // Plugin and core grants: the exact reviewed list, unchanged by the lockdown.
+        let (bare, prefixed): (Vec<String>, Vec<String>) =
+            listed.iter().cloned().partition(|g| !g.contains(':'));
+        let mut sorted = prefixed;
         sorted.sort();
         let mut expected = vec![
             "core:event:allow-listen",
@@ -716,16 +923,35 @@ mod tests {
             "core:webview:allow-internal-toggle-devtools",
             "dialog:allow-open",
             "dialog:allow-save",
-            "opener:allow-open-url",
         ];
         expected.sort();
         assert_eq!(
             sorted, expected,
-            "the capability set changed. That is allowed — but it is the IPC \
+            "the plugin/core capability set changed. That is allowed — but it is the IPC \
              surface a compromised webview can call, so update this list \
              deliberately rather than to make the test pass."
         );
 
+        // App commands: since build.rs declares the AppManifest, the bare `allow-*` grants
+        // are the complete list of app commands the main window may call. `build.rs` already
+        // fails the build when they disagree with generate_handler!; this keeps the reviewed
+        // rule ("every non-viewer command, exactly") visible where the plugin census lives.
+        let registered = crate::command_census::registered_commands(include_str!("lib.rs"))
+            .expect("lib.rs should contain a generate_handler! list");
+        let mut expected_bare: Vec<String> = registered
+            .iter()
+            .filter(|c| crate::command_census::expected_windows(c) == ["main"])
+            .map(|c| crate::command_census::allow_permission(c))
+            .collect();
+        expected_bare.sort();
+        let mut bare = bare;
+        bare.sort();
+        assert_eq!(
+            bare, expected_bare,
+            "default.json's app-command grants must be exactly the main-window commands"
+        );
+        assert!(bare.len() >= 100, "the census found {} app grants; the parser has stopped seeing the list", bare.len());
+
         // Belt and braces: the `*:default` aliases are the specific trap here,
         // because they expand to a set the file never spells out. `store:*` in
         // particular was an arbitrary host-file read/write primitive.
@@ -743,4 +969,100 @@ mod tests {
             );
         }
     }
+
+    /// `build.rs` derives the AppManifest from the handler list and this reads back what
+    /// tauri-build actually embedded. `cargo test` runs the build script first, so
+    /// `gen/schemas/acl-manifests.json` is fresh. This guards against the committed/generated
+    /// artifact diverging from `generate_handler!` — a stale `acl-manifests.json`, or a
+    /// tauri-build naming change — using the same `registered_commands` parser `build.rs` used
+    /// to derive the manifest in the first place. It is *not* independent of a parser dropout on
+    /// its own: if `registered_commands` lost half the list, `build.rs` would declare half a
+    /// manifest and this would still compare it against the same half. That guarantee is
+    /// transitive, not local — `every_command_is_registered_exactly_once` covers it, by
+    /// cross-checking the parser's output against an independent `#[tauri::command]` scan, so a
+    /// parser regression that silently dropped commands fails there rather than going unnoticed
+    /// here.
+    #[test]
+    fn the_generated_app_manifest_matches_the_handler_list() {
+        use std::collections::BTreeSet;
+
+        let path = concat!(env!("CARGO_MANIFEST_DIR"), "/gen/schemas/acl-manifests.json");
+        let raw = std::fs::read_to_string(path)
+            .expect("gen/schemas/acl-manifests.json is written by build.rs on every build");
+        let manifests: serde_json::Value =
+            serde_json::from_str(&raw).expect("acl-manifests.json must parse");
+        let app = manifests.get("__app-acl__").expect(
+            "build.rs must declare an AppManifest — without it tauri skips the ACL for every \
+             app command",
+        );
+        let embedded: BTreeSet<String> = app["permissions"]
+            .as_object()
+            .expect("the app manifest has a permissions map")
+            .keys()
+            .cloned()
+            .collect();
+
+        let registered = crate::command_census::registered_commands(include_str!("lib.rs"))
+            .expect("lib.rs should contain a generate_handler! list");
+        let expected: BTreeSet<String> = registered
+            .iter()
+            .flat_map(|c| {
+                let allow = crate::command_census::allow_permission(c);
+                let deny = format!("deny-{}", &allow["allow-".len()..]);
+                [allow, deny]
+            })
+            .collect();
+
+        assert!(registered.len() >= 100, "the parser sees {} commands", registered.len());
+        assert_eq!(
+            embedded, expected,
+            "the embedded app manifest and generate_handler! disagree: build.rs and \
+             tauri-build should have produced the same list"
+        );
+        assert!(
+            app["permission_sets"].as_object().is_some_and(|s| s.is_empty()),
+            "no permission sets: every grant is a literal allow-* string in a capability file"
+        );
+        assert!(app["default_permission"].is_null(), "no app `default` permission set");
+    }
+
+    /// `build.rs`'s `check_tauri_config` (inline `app.security.capabilities`, a JSON5/TOML tauri
+    /// config, `TAURI_CONFIG`) only runs inside the build script, so it only re-runs on a clean
+    /// build or in CI — cargo's incremental build has no reason to notice a new
+    /// `tauri.<platform>.conf.json` dropped into an already-built tree (CLAUDE.md, "Known
+    /// limit"). This runs the same check, using the same `command_census` functions build.rs
+    /// calls, directly against the real `app/src-tauri` directory on every `cargo test`, so that
+    /// gap is closed locally too.
+    #[test]
+    fn the_tauri_config_capability_check_runs_against_the_real_tree() {
+        let dir = env!("CARGO_MANIFEST_DIR");
+        let mut problems = Vec::new();
+        for entry in std::fs::read_dir(dir).expect("readable src-tauri/") {
+            let path = entry.expect("readable entry in src-tauri/").path();
+            let name = path
+                .file_name()
+                .expect("a directory entry has a file name")
+                .to_string_lossy()
+                .into_owned();
+            match crate::command_census::tauri_config_file(&name) {
+                None => {}
+                Some(false) => problems.push(format!(
+                    "{name}: the census reads JSON tauri configs only; a JSON5/TOML config \
+                     could declare capabilities it cannot see"
+                )),
+                Some(true) => {
+                    let json =
+                        std::fs::read_to_string(&path).unwrap_or_else(|e| panic!("{name}: {e}"));
+                    problems.extend(crate::command_census::tauri_config_problem(&name, &json));
+                }
+            }
+        }
+        if let Ok(json) = std::env::var("TAURI_CONFIG") {
+            problems.extend(crate::command_census::tauri_config_problem("TAURI_CONFIG", &json));
+        }
+        assert!(
+            problems.is_empty(),
+            "cargo test found what build.rs would refuse on a clean build: {problems:?}"
+        );
+    }
 }

app/src-tauri/src/main.rs

@@ -1,6 +1,157 @@
 // Prevents additional console window on Windows in release
 #![cfg_attr(not(debug_assertions), windows_subsystem = "windows")]
 
+/// WebKitGTK's DMA-BUF renderer (its default accelerated-compositing path
+/// since 2.42) fails outright on some Mesa/driver/compositor combinations
+/// under Wayland, killing the webview and leaving a blank window — see
+/// triple-c#34, reported on CachyOS/Arch with Wayland.
+///
+/// **This is not the only cause of a blank window, and the error text alone
+/// does not tell them apart.** An earlier version of this comment quoted
+/// `Could not create default EGL display: EGL_BAD_PARAMETER. Aborting.` as
+/// the error this fixes. The AppImage produces that same string for an
+/// entirely unrelated reason: it bundled a `libwayland-client.so.0` that
+/// shadowed the host's, and the host's `libEGL_mesa.so.0` has a hard
+/// DT_NEEDED on that library, so the EGL driver failed to load before any
+/// renderer choice was reachable. This flag was set, and correctly, and made no difference —
+/// which cost a round of debugging that started from the comment rather than
+/// from the evidence. See `scripts/unbundle-wayland-client.sh`.
+///
+/// Set unconditionally on Linux rather than gated on `WAYLAND_DISPLAY`: that
+/// variable is exported into an XWayland client's environment too, so a
+/// gate on it wouldn't even cleanly separate "Wayland" from "X11" — and
+/// there is no reliable heuristic at all for the actual variable that
+/// matters, which Mesa/driver/compositor combination is affected. This is
+/// the blunt instrument, chosen deliberately because the fallback is a real
+/// trade, not a free one: the terminal's `@xterm/addon-webgl` renderer
+/// (`TerminalView.tsx`) is the one surface in this app actually asking for
+/// GPU compositing, and it degrades to xterm's canvas renderer under this
+/// setting — slower on very heavy output, but the addon's own construction
+/// is already wrapped in a fallback (`WebGL not available` is a handled
+/// case, not a crash), so this is a real but graceful downgrade, traded
+/// against a startup abort that has no fallback at all.
+///
+/// Must be set before `triple_c_lib::run()` — GTK/WebKitGTK reads it at
+/// their own init time, which happens inside the Tauri builder that
+/// function calls into, not at binary load.
+///
+/// A user who has already set this themselves is left alone — with one
+/// correction. The earlier version of this function left *any* pre-set value
+/// alone, including `0`, on the assumption WebKitGTK reads the variable as a
+/// boolean. WebKitGTK reads it as presence-only, so `WEBKIT_DISABLE_DMABUF_
+/// RENDERER=0` disabled DMA-BUF exactly like `=1` did, and there was no value
+/// at all a user could set to get the accelerated path back: the escape hatch
+/// the comment described did not exist. `0`, `false` and empty are now treated
+/// as an explicit opt-out and the variable is *removed*, which is the only
+/// thing WebKitGTK reads as "enabled". The default is unchanged — unset still
+/// means disabled on Linux, so nobody who was not deliberately overriding this
+/// sees any difference.
+///
+/// That matters more than it looks, because the trade described above is not
+/// the trade actually being made. `@xterm/addon-webgl` does not fall back to
+/// the canvas renderer here: its constructor throws only when WebGL is
+/// *absent*, and with DMA-BUF disabled WebGL is still present — served by
+/// software rasterisation. So the addon loads happily and every terminal frame
+/// is rendered on the CPU and copied, which is slower than the canvas renderer
+/// this comment assumed it would degrade to, not faster. See
+/// `terminal_gpu_rendering` in `AppSettings` for the switch that decides
+/// whether the addon is loaded at all.
+///
+/// This env var also leaks to whatever the app spawns afterwards — notably
+/// a cold-launched default browser via the `opener` plugin's `xdg-open`
+/// call. Narrow in practice (an already-running browser just receives the
+/// URL; most non-WebKitGTK browsers ignore the variable entirely), but
+/// worth knowing before chasing the "links don't open" half of triple-c#34
+/// as a separate, unrelated cause.
+///
+/// That leak is now plugged rather than merely documented: `url_open` hands
+/// the opener a child environment with this variable (and the AppImage's own
+/// `LD_LIBRARY_PATH`/`GTK_PATH`/... ) restored or removed. Setting it here
+/// stays process-wide because GTK/WebKitGTK need it; what changed is that the
+/// children no longer inherit it.
+#[cfg(target_os = "linux")]
+const DMABUF_VAR: &str = "WEBKIT_DISABLE_DMABUF_RENDERER";
+
+/// What to do with `WEBKIT_DISABLE_DMABUF_RENDERER`, given whatever it is
+/// already set to. Split from the mutation so it can be tested without
+/// touching process-wide environment state from a parallel test runner.
+#[cfg(target_os = "linux")]
+#[derive(Debug, PartialEq, Eq)]
+enum DmabufAction {
+    /// Not set by the user — apply the workaround.
+    Disable,
+    /// Explicitly opted out. WebKitGTK reads presence, not value, so the only
+    /// way to express "enabled" is for the variable not to exist.
+    Remove,
+    /// Set to something meaning "disabled". Already what we want; leave it.
+    LeaveAlone,
+}
+
+#[cfg(target_os = "linux")]
+fn dmabuf_action(current: Option<&str>) -> DmabufAction {
+    match current {
+        None => DmabufAction::Disable,
+        Some(value) => match value.trim().to_ascii_lowercase().as_str() {
+            "" | "0" | "false" | "no" => DmabufAction::Remove,
+            _ => DmabufAction::LeaveAlone,
+        },
+    }
+}
+
+#[cfg(target_os = "linux")]
+fn apply_webkit_wayland_workaround() {
+    let current = std::env::var(DMABUF_VAR).ok();
+    match dmabuf_action(current.as_deref()) {
+        DmabufAction::Disable => std::env::set_var(DMABUF_VAR, "1"),
+        DmabufAction::Remove => std::env::remove_var(DMABUF_VAR),
+        DmabufAction::LeaveAlone => {}
+    }
+}
+
+#[cfg(all(test, target_os = "linux"))]
+mod tests {
+    use super::{dmabuf_action, DmabufAction};
+
+    #[test]
+    fn unset_gets_the_workaround() {
+        assert_eq!(dmabuf_action(None), DmabufAction::Disable);
+    }
+
+    #[test]
+    fn falsey_values_opt_out_by_removing_the_variable() {
+        // The bug this replaces: these all previously read as "user set it,
+        // leave it alone", and WebKitGTK then disabled DMA-BUF anyway because
+        // it only checks presence. There was no way to ask for the GPU path.
+        for value in ["0", "false", "no", "", "  0  ", "FALSE", "No"] {
+            assert_eq!(
+                dmabuf_action(Some(value)),
+                DmabufAction::Remove,
+                "{value:?} should opt out"
+            );
+        }
+    }
+
+    #[test]
+    fn other_values_are_left_alone() {
+        for value in ["1", "true", "yes", "anything"] {
+            assert_eq!(
+                dmabuf_action(Some(value)),
+                DmabufAction::LeaveAlone,
+                "{value:?} should be left alone"
+            );
+        }
+    }
+}
+
 fn main() {
+    // Before *any* `std::env::set_var` — `url_open` hands a child process the
+    // environment this app was started with, and the workaround below is one
+    // of the things that must not leak into it (see triple-c#34). Anything
+    // added here that mutates the environment belongs after this line.
+    triple_c_lib::url_open::capture_pristine_environment();
+
+    #[cfg(target_os = "linux")]
+    apply_webkit_wayland_workaround();
+
     triple_c_lib::run()
 }

app/src-tauri/src/models/app_settings.rs

@@ -135,6 +135,26 @@ pub struct AppSettings {
     pub gateway: GatewaySettings,
     #[serde(default)]
     pub global_claude_code_settings: Option<ClaudeCodeSettings>,
+    /// Whether the terminal loads `@xterm/addon-webgl`.
+    ///
+    /// `None` is "auto", and auto is not the same answer on every platform.
+    /// On Linux the app disables WebKitGTK's DMA-BUF renderer at startup (see
+    /// `apply_webkit_wayland_workaround` in `main.rs`, and triple-c#34), which
+    /// does not remove WebGL — it leaves it backed by software rasterisation.
+    /// The addon therefore loads successfully and then renders every frame on
+    /// the CPU, which is slower than the canvas renderer it would otherwise
+    /// have fallen back to. So auto means enabled on macOS and Windows, and
+    /// disabled on Linux.
+    ///
+    /// `Some(true)` / `Some(false)` force it either way on any platform. A
+    /// Linux user running X11, or one whose driver stack is unaffected, can
+    /// turn it back on; anyone seeing terminal lag can turn it off without
+    /// waiting for a release. Deliberately `Option<bool>` rather than `bool`:
+    /// the zero value has to mean "we choose", not "off", or every existing
+    /// settings file would silently pin the answer at whatever the default was
+    /// the day it was written.
+    #[serde(default)]
+    pub terminal_gpu_rendering: Option<bool>,
 }
 
 fn default_stt_model() -> String {
@@ -226,6 +246,7 @@ impl Default for AppSettings {
             stt: SttSettings::default(),
             gateway: GatewaySettings::default(),
             global_claude_code_settings: None,
+            terminal_gpu_rendering: None,
         }
     }
 }

app/src-tauri/src/models/mod.rs

@@ -1,13 +1,17 @@
-pub mod project;
-pub mod container_config;
 pub mod app_settings;
+pub mod container_config;
 pub mod gateway_settings;
 pub mod migration;
+pub mod note;
+pub mod project;
+pub mod settings_export;
 pub mod update_info;
 
-pub use project::*;
-pub use container_config::*;
 pub use app_settings::*;
+pub use container_config::*;
 pub use gateway_settings::*;
 pub use migration::*;
+pub use note::*;
+pub use project::*;
+pub use settings_export::*;
 pub use update_info::*;

app/src-tauri/src/models/note.rs

@@ -0,0 +1,34 @@
+use serde::{Deserialize, Serialize};
+
+/// One note. A scratchpad entry the user can also fire at a running Claude
+/// session.
+///
+/// Deliberately has no `kind`/`type` field. What makes a note "for the agent"
+/// is that the user pressed Send, not a mode chosen when it was written — a
+/// classification decision at writing time is one the user is least willing to
+/// make, and it would turn one pane into two features.
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+pub struct Note {
+    pub id: String,
+    pub title: String,
+    pub body: String,
+    /// Pinned notes sort first, then by `updated_at` descending.
+    #[serde(default)]
+    pub pinned: bool,
+    pub created_at: String,
+    pub updated_at: String,
+}
+
+impl Note {
+    pub fn new(title: String, body: String) -> Self {
+        let now = chrono::Utc::now().to_rfc3339();
+        Self {
+            id: uuid::Uuid::new_v4().to_string(),
+            title,
+            body,
+            pinned: false,
+            created_at: now.clone(),
+            updated_at: now,
+        }
+    }
+}

app/src-tauri/src/models/project.rs

@@ -8,6 +8,100 @@ pub struct EnvVar {
     pub value: String,
 }
 
+/// Whether `key` is a name a shell will read back as an ordinary variable:
+/// `[A-Za-z_][A-Za-z0-9_]*`.
+///
+/// ## Why a charset rule, and not just the reserved-name list
+///
+/// `docker::container::is_reserved_env_key` answers a different question — "is
+/// this one of the names Triple-C manages itself" — and nothing anywhere asked
+/// what the *characters* were. A key is joined into `KEY=VALUE` and handed to
+/// the daemon, which puts it in the container's environment verbatim, so a name
+/// that is not an identifier travels through unchallenged.
+///
+/// The one that matters is `BASH_FUNC_name%%`, bash's wire format for an
+/// exported shell function: bash imports those at startup and the *body* is the
+/// value. Today that is latent rather than live — the image's `/bin/sh` is
+/// dash, which does not import them, and an auditor confirmed the vector fires
+/// under `bash -c` and not under `sh -c` in the shipped image. But the
+/// pre-commit scrub runs `/bin/sh -c` **as root**, `/bin/sh` is whatever
+/// `ubuntu:24.04` points it at, and nothing pins that. One base-image change,
+/// or one call site spelled `bash`, turns a stored project setting into root
+/// code execution inside the container at commit time.
+///
+/// So the rule is the shape of the thing rather than a list of the names that
+/// are known to be dangerous: `IFS`, `LD_PRELOAD` and `PATH` are all perfectly
+/// good identifiers and are the user's business, while nothing legitimate needs
+/// a `%`, a `(` or a space in an environment variable name.
+///
+/// The key is judged **trimmed**, because that is what `create_container` sends
+/// — ` FOO ` already reaches the container as `FOO`, and refusing it here would
+/// break a setting that works.
+pub fn is_valid_env_key(key: &str) -> bool {
+    let mut chars = key.trim().chars();
+    match chars.next() {
+        Some(c) if c.is_ascii_alphabetic() || c == '_' => {}
+        _ => return false,
+    }
+    chars.all(|c| c.is_ascii_alphanumeric() || c == '_')
+}
+
+/// Validate a custom environment variable list that is about to be stored,
+/// admitting the entries it is already stored with.
+///
+/// Same shape, and the same reasoning, as
+/// `commands::project_commands::validate_project_paths_update`: nothing ever
+/// checked these keys, so `projects.json` and `settings.json` in the field can
+/// hold whatever was typed. Holding every save to the new rule would make such
+/// a project unsavable *entirely* — `update_project` is the single command
+/// behind the whole Config tab — and would buy nothing, because the stored key
+/// is already being handed to every container that starts. An entry carried
+/// over verbatim is admitted; a new or edited one is held to the rule, which is
+/// what keeps the escalation closed, since escalation means *introducing* a bad
+/// key through this command.
+///
+/// Counted rather than set-tested, for the same reason as the folder rows: a
+/// second copy of an existing entry is a new entry.
+///
+/// The blank entry is not a violation. "+ Add variable" appends
+/// `{key: "", value: ""}` and saves the list immediately, so refusing it would
+/// turn the button itself into an error toast; `create_container` skips an
+/// empty key, so it reaches nothing.
+pub fn validate_env_vars_update(stored: &[EnvVar], incoming: &[EnvVar]) -> Result<(), String> {
+    // An entry with no key is the placeholder, whatever is in its value:
+    // `create_container` skips it, so it reaches nothing and there is nothing
+    // to refuse. The editor saves on every blur, and typing the value before
+    // the name is an ordinary way to fill a row in.
+    let is_blank = |v: &EnvVar| v.key.trim().is_empty();
+
+    let mut carried: std::collections::HashMap<(&str, &str), usize> =
+        std::collections::HashMap::new();
+    for v in stored.iter().filter(|v| !is_blank(v)) {
+        *carried
+            .entry((v.key.as_str(), v.value.as_str()))
+            .or_insert(0) += 1;
+    }
+
+    for v in incoming.iter().filter(|v| !is_blank(v)) {
+        match carried.get_mut(&(v.key.as_str(), v.value.as_str())) {
+            Some(remaining) if *remaining > 0 => {
+                *remaining -= 1;
+            }
+            _ => {
+                if !is_valid_env_key(&v.key) {
+                    return Err(format!(
+                        "'{}' is not a usable environment variable name. Use a letter or \
+                         underscore followed by letters, digits or underscores.",
+                        v.key
+                    ));
+                }
+            }
+        }
+    }
+
+    Ok(())
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
 pub struct ProjectPath {
     pub host_path: String,
@@ -38,6 +132,26 @@ fn default_use_shared_auth_token() -> bool {
     true
 }
 
+/// `auth_bridge_enabled` defaults to **on**, and the default is what makes
+/// `claude login` work at all.
+///
+/// The login flow binds a *random* ephemeral loopback port inside the
+/// container and then sends the host's browser to `127.0.0.1:<that port>`.
+/// On the host nothing is listening there, so the callback lands on a closed
+/// port and the CLI waits for a redirect that can never arrive. The bridge
+/// mirrors the container's loopback listeners onto the same host port, which
+/// is the only thing that closes that loop — so off-by-default made a hang the
+/// out-of-the-box experience.
+///
+/// Returning `true` from a `#[serde(default)]` helper (rather than flipping the
+/// constructor alone) is deliberate: existing `projects.json` records were
+/// written before this field existed, or while it was off, and an absent key is
+/// what the default is read for. A project that wants the old behaviour turns
+/// the toggle off, which persists an explicit `false`.
+fn default_auth_bridge_enabled() -> bool {
+    true
+}
+
 /// How much autonomy Claude Code is granted inside the container.
 ///
 /// Maps onto Claude Code CLI flags — see [`PermissionMode::cli_args`], which is
@@ -85,6 +199,7 @@ impl PermissionMode {
 /// Settings for Claude Code CLI behavior inside the container.
 /// These map to Claude Code env vars and ~/.claude/settings.json entries.
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Default)]
+#[serde(from = "StoredClaudeCodeSettings")]
 /// Every field is three-state, and the third state is load-bearing.
 ///
 /// `None` means "not set at this level". For a *project* that is "inherit
@@ -98,24 +213,24 @@ pub struct ClaudeCodeSettings {
     /// what lets Claude Code pick the renderer itself; `Some("default")` pins
     /// the classic main-screen renderer and `Some("fullscreen")` the alt-screen
     /// one. All three are distinct — "let it choose" is not "classic".
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub tui_mode: Option<String>,
     /// Saved `/effort` level: `None` = unset, otherwise one of
     /// `"low" | "medium" | "high" | "xhigh"`. Written to settings.json as
     /// `effortLevel` (**not** `effort`, which Claude Code has never read).
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub effort: Option<String>,
     /// Disable auto-scroll in fullscreen TUI mode. Held in the *disabled* sense
     /// because Claude Code's `autoScrollEnabled` defaults to `true`, so the
     /// zero value of this field has to mean "leave it on".
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub auto_scroll_disabled: Option<bool>,
     /// Collapse tool output to one-line summaries. Written to settings.json as
     /// `viewMode: "focus"`; there is no `focusMode` key in Claude Code.
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub focus_mode: Option<bool>,
     /// Show thinking summaries in responses
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub show_thinking_summaries: Option<bool>,
     /// Turn the session recap **off**.
     ///
@@ -128,16 +243,99 @@ pub struct ClaudeCodeSettings {
     /// never touched the control holds — as "the user turned the recap off" and
     /// silently disabled it for all of them. A new name lets the old key be
     /// ignored, which lands every existing project on the correct default.
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub session_recap_disabled: Option<bool>,
     /// Strip credentials from subprocess environments
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub env_scrub: Option<bool>,
     /// Enable 1-hour prompt cache TTL (vs default 5-minute)
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub prompt_caching_1h: Option<bool>,
 }
 
+/// `ClaudeCodeSettings` in every shape `projects.json` and `settings.json` can
+/// be holding, which is what [`ClaudeCodeSettings`] is actually deserialised
+/// through.
+///
+/// ## The upgrade this exists to survive
+///
+/// Before the widening, the five booleans were plain `bool`s with
+/// `#[serde(default)]` and no `skip_serializing_if`, so **every** settings
+/// object ever written carries an explicit `"env_scrub": false` — not because
+/// anyone chose it, but because that is what a `bool` serialises to. Under the
+/// old merge (`if p.x { true } else { g.x }`) that `false` carried no
+/// information at all: it was the only value an unset switch could produce, and
+/// the global always won.
+///
+/// Read as `Some(false)` by the new code it becomes a *deliberate off* that
+/// beats a global `Some(true)` — so upgrading silently turned five settings off
+/// for every project that had ever opened this editor, `env_scrub` ("strip
+/// credentials from subprocess environments") among them. There is no store
+/// migration anywhere: `projects_store` parses these structs directly.
+///
+/// ## How an old record is told apart from a new one
+///
+/// By `enable_session_recap`. It was in the struct from the day it existed and
+/// was a plain `bool`, so its key is present in every pre-widening record and
+/// in no other — the field was *renamed* to `session_recap_disabled` precisely
+/// so the old key could be ignored (see the doc on that field), and the new
+/// code has never written it. Its presence is therefore an exact statement that
+/// these bytes were written by a binary in which `false` meant "unset", and the
+/// booleans are read back that way: `true` is a real choice and survives,
+/// `false` becomes `None` and inherits again.
+///
+/// Nothing marks a *new* record, and nothing needs to: absent is `None` (the
+/// fields skip serialising when unset) and a present `false` is the deliberate
+/// off the widening was for. That is also what keeps a downgrade survivable —
+/// an older binary reads an absent key as `false` through its own
+/// `#[serde(default)]`, where a `null` would fail to parse and take the whole
+/// of `projects.json` down with it, since `ProjectsStore` parses all-or-nothing
+/// and starts empty on an error.
+#[derive(Deserialize)]
+struct StoredClaudeCodeSettings {
+    #[serde(default)]
+    tui_mode: Option<String>,
+    #[serde(default)]
+    effort: Option<String>,
+    #[serde(default)]
+    auto_scroll_disabled: Option<bool>,
+    #[serde(default)]
+    focus_mode: Option<bool>,
+    #[serde(default)]
+    show_thinking_summaries: Option<bool>,
+    #[serde(default)]
+    session_recap_disabled: Option<bool>,
+    #[serde(default)]
+    env_scrub: Option<bool>,
+    #[serde(default)]
+    prompt_caching_1h: Option<bool>,
+    /// The pre-widening spelling of `session_recap_disabled`, and the *only*
+    /// use of its value: presence dates the record. Its meaning was inverted
+    /// and it never worked, so it is read for the marker and discarded.
+    #[serde(default)]
+    enable_session_recap: Option<bool>,
+}
+
+impl From<StoredClaudeCodeSettings> for ClaudeCodeSettings {
+    fn from(stored: StoredClaudeCodeSettings) -> Self {
+        let pre_widening = stored.enable_session_recap.is_some();
+        // On a pre-widening record `false` is what an untouched switch wrote,
+        // so it means "not set at this level" and must inherit. A `true` was a
+        // real choice either way.
+        let read = |v: Option<bool>| if pre_widening { v.filter(|on| *on) } else { v };
+        ClaudeCodeSettings {
+            tui_mode: stored.tui_mode,
+            effort: stored.effort,
+            auto_scroll_disabled: read(stored.auto_scroll_disabled),
+            focus_mode: read(stored.focus_mode),
+            show_thinking_summaries: read(stored.show_thinking_summaries),
+            session_recap_disabled: read(stored.session_recap_disabled),
+            env_scrub: read(stored.env_scrub),
+            prompt_caching_1h: read(stored.prompt_caching_1h),
+        }
+    }
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct Project {
     pub id: String,
@@ -158,17 +356,30 @@ pub struct Project {
     pub sandbox_mode_enabled: bool,
     #[serde(default)]
     pub mission_control_enabled: bool,
-    /// Opt in to the auth bridge: while the container runs, its loopback
-    /// listeners are mirrored onto the host's loopback so browser OAuth
-    /// callbacks (`claude login`, `fly login`, `aws sso login`) can reach them.
+    /// The auth bridge: while the container runs, its loopback listeners are
+    /// mirrored onto the host's loopback so browser OAuth callbacks
+    /// (`claude login`, `fly login`, `aws sso login`) can reach them.
     /// Purely host-side — it deliberately has no container-recreation label,
     /// because toggling it changes nothing about the container itself.
-    #[serde(default)]
+    ///
+    /// **On by default**, and opt-*out* rather than opt-in — see
+    /// [`default_auth_bridge_enabled`] for why the default is the feature.
+    #[serde(default = "default_auth_bridge_enabled")]
     pub auth_bridge_enabled: bool,
     /// Opt in to the browser-view pane, which watches and takes over the
     /// browser Claude drives with Playwright inside the container. Purely
     /// host-side like `auth_bridge_enabled`, so it likewise has no
     /// container-recreation label.
+    ///
+    /// This is the *durable* home of the flag: `BrowserViewManager` reads it
+    /// rather than keeping its own copy, so the pane comes back the way it was
+    /// left. Off by default, and unlike the auth bridge it stays that way — a
+    /// view costs a container exec, a Node daemon and a host port, and a
+    /// container without Playwright cannot serve one at all.
+    ///
+    /// Durable does **not** mean auto-started: nothing brings a viewer up on
+    /// app start, so a project left enabled reports `enabled` with a state of
+    /// `Off` until the pane (or `open_page_in_container_browser`) asks for one.
     #[serde(default)]
     pub browser_view_enabled: bool,
     /// Grant the container what a VPN client needs to build a tunnel:
@@ -244,6 +455,61 @@ pub enum ProjectStatus {
     Error,
 }
 
+/// What `remove_project` could not delete, named so the UI can say so instead
+/// of reporting a clean removal that was not one.
+///
+/// The project record is dropped from `projects.json` regardless — see the
+/// long comment on `remove_project` for why refusing is not the answer — but
+/// anything named here is also written to a pending-cleanup record that
+/// startup housekeeping retries, so it stays reachable after the project it
+/// belonged to no longer exists.
+#[derive(Debug, Default, Clone, Serialize, Deserialize)]
+pub struct ProjectRemovalReport {
+    /// The project's container, if it could not be removed. Named by its
+    /// deterministic `triple-c-{id}` name (see `Project::container_name`),
+    /// not the container id, since the id can be stale or absent and the
+    /// name is what a later retry can still resolve.
+    pub container: Option<String>,
+    /// The `triple-c-snapshot-{id}` image, if it could not be removed.
+    pub image: Option<String>,
+    /// Named volumes (home, claude config) that could not be removed.
+    pub volumes: Vec<String>,
+    /// True once the leftovers above were durably recorded for automatic
+    /// retry on the next launch. False means the pending-cleanup record
+    /// itself could not be written — nothing will retry these, and the UI
+    /// must say so rather than promising a retry that will not happen.
+    /// Meaningless (and left at its default) when `is_clean()` is true.
+    pub retry_scheduled: bool,
+}
+
+impl ProjectRemovalReport {
+    /// True when nothing was left behind.
+    pub fn is_clean(&self) -> bool {
+        self.container.is_none() && self.image.is_none() && self.volumes.is_empty()
+    }
+}
+
+/// What `rebuild_project_container` (Reset) produced: the project as it
+/// stands after restarting, and anything Reset could not clear.
+///
+/// Reset's contract is "back to a clean base image", so a leftover volume or
+/// image here is reused/rebuilt-from as-is by the container this creates —
+/// the opposite of what was asked for — and unlike [`ProjectRemovalReport`]
+/// there is no pending-cleanup record for either: the project id survives
+/// Reset, so a later Reset attempt can retry them itself.
+#[derive(Debug, Clone, Serialize)]
+pub struct ProjectResetOutcome {
+    pub project: Project,
+    /// The `triple-c-snapshot-{id}` image, if Reset could not remove it. The
+    /// more serious of the two leftovers here: the new container is created
+    /// from this image whenever it exists, so a surviving image means Reset
+    /// silently rebuilt the exact system layer it was asked to discard.
+    pub leftover_image: Option<String>,
+    /// Volumes that survived Reset and were mounted into the new container
+    /// unchanged.
+    pub leftover_volumes: Vec<String>,
+}
+
 /// Which AI model backend/provider the project uses.
 /// - `Anthropic`: Direct Anthropic API (user runs `claude login` inside the container)
 /// - `Bedrock`: AWS Bedrock with per-project AWS credentials
@@ -406,7 +672,7 @@ impl Project {
             allow_docker_access: false,
             sandbox_mode_enabled: false,
             mission_control_enabled: false,
-            auth_bridge_enabled: false,
+            auth_bridge_enabled: default_auth_bridge_enabled(),
             browser_view_enabled: false,
             vpn_support_enabled: false,
             use_shared_auth_token: default_use_shared_auth_token(),
@@ -467,3 +733,254 @@ impl Project {
         val
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    // ── ProjectRemovalReport ────────────────────────────────────────────────
+
+    #[test]
+    fn a_report_is_clean_only_with_nothing_left_behind() {
+        assert!(ProjectRemovalReport::default().is_clean());
+
+        let mut r = ProjectRemovalReport::default();
+        r.container = Some("abc123".to_string());
+        assert!(!r.is_clean(), "a leftover container must not read as clean");
+
+        let mut r = ProjectRemovalReport::default();
+        r.image = Some("triple-c-snapshot-x:latest".to_string());
+        assert!(!r.is_clean(), "a leftover image must not read as clean");
+
+        let mut r = ProjectRemovalReport::default();
+        r.volumes.push("triple-c-home-x".to_string());
+        assert!(!r.is_clean(), "a leftover volume must not read as clean");
+    }
+
+    // ── Custom environment variable names ─────────────────────────────────
+
+    #[test]
+    fn an_env_var_name_has_to_be_a_shell_identifier() {
+        for ok in ["PATH", "_", "_x", "MY_VAR2", "a", " SPACED_BY_THE_EDITOR "] {
+            assert!(is_valid_env_key(ok), "'{}' should be a usable name", ok);
+        }
+        for bad in [
+            // bash's wire format for an exported shell function: the value is
+            // the body, and a `bash` that imports it runs it. The scrub exec is
+            // `/bin/sh -c` as root, and nothing pins `/bin/sh` to dash.
+            "BASH_FUNC_stat%%",
+            "BASH_FUNC_ls()",
+            "MY VAR",
+            "2FAST",
+            "WITH-DASH",
+            "WITH.DOT",
+            "",
+            "   ",
+            "$(id)",
+            "A=B",
+        ] {
+            assert!(!is_valid_env_key(bad), "'{}' should be refused", bad);
+        }
+    }
+
+    fn env(key: &str, value: &str) -> EnvVar {
+        EnvVar { key: key.to_string(), value: value.to_string() }
+    }
+
+    #[test]
+    fn a_bad_env_var_name_cannot_be_introduced_but_a_stored_one_does_not_brick_the_editor() {
+        let bad = [env("BASH_FUNC_stat%%", "() { id; }")];
+        // Introducing it through the Config tab is the escalation.
+        assert!(validate_env_vars_update(&[], &bad).is_err());
+        // Already stored: it is handed to every container that starts whether
+        // or not an unrelated save is allowed through, and refusing the save
+        // would make every toggle on the Config tab fail.
+        assert!(validate_env_vars_update(&bad, &bad).is_ok());
+        // Editing its value is a new entry, and refused again.
+        assert!(
+            validate_env_vars_update(&bad, &[env("BASH_FUNC_stat%%", "() { rm -rf /; }")]).is_err()
+        );
+        // Fixing the name is what the message asks for, and it saves.
+        assert!(validate_env_vars_update(&bad, &[env("STAT", "() { id; }")]).is_ok());
+        // Dropping it entirely is always fine.
+        assert!(validate_env_vars_update(&bad, &[]).is_ok());
+    }
+
+    #[test]
+    fn the_blank_row_the_add_button_saves_is_not_an_error() {
+        // "+ Add variable" appends an empty entry and saves the list at once,
+        // so this is the button, not an attempt at anything.
+        assert!(validate_env_vars_update(&[], &[env("", "")]).is_ok());
+        // Typing the value before the name is an ordinary way to fill it in,
+        // and an entry with no name reaches no container either way.
+        assert!(validate_env_vars_update(&[], &[env("", "value-first")]).is_ok());
+        assert!(validate_env_vars_update(&[], &[env("GOOD", "v"), env("", "")]).is_ok());
+    }
+
+    #[test]
+    fn a_stored_entry_may_be_kept_but_not_multiplied() {
+        let stored = [env("BAD NAME", "v")];
+        assert!(validate_env_vars_update(&stored, &stored).is_ok());
+        // A second copy is a new entry, and held to the rule.
+        assert!(
+            validate_env_vars_update(&stored, &[env("BAD NAME", "v"), env("BAD NAME", "v")])
+                .is_err()
+        );
+    }
+
+    // ── Claude Code settings written before the fields were widened ───────
+
+    /// `projects.json` exactly as the shipped `main` binary wrote it: the five
+    /// booleans were plain `bool`s that always serialised, so every project
+    /// that ever opened the editor carries `false` for the ones it never
+    /// touched.
+    const MAIN_SHAPE_PROJECT: &str = r#"{
+        "id": "p1",
+        "name": "demo",
+        "paths": [{ "host_path": "/home/u/demo", "mount_name": "demo" }],
+        "container_id": null,
+        "status": "stopped",
+        "backend": "anthropic",
+        "bedrock_config": null,
+        "ollama_config": null,
+        "openai_compatible_config": null,
+        "allow_docker_access": false,
+        "ssh_key_path": null,
+        "git_user_name": null,
+        "git_user_email": null,
+        "claude_code_settings": {
+            "tui_mode": "fullscreen",
+            "effort": null,
+            "auto_scroll_disabled": false,
+            "focus_mode": false,
+            "show_thinking_summaries": false,
+            "enable_session_recap": false,
+            "env_scrub": false,
+            "prompt_caching_1h": false
+        },
+        "created_at": "2026-01-01T00:00:00Z",
+        "updated_at": "2026-01-01T00:00:00Z"
+    }"#;
+
+    #[test]
+    fn a_setting_stored_as_false_by_the_old_binary_still_inherits_the_global() {
+        let project: Project = serde_json::from_str(MAIN_SHAPE_PROJECT).unwrap();
+        let stored = project.claude_code_settings.expect("settings should parse");
+
+        // Read verbatim these would be `Some(false)`, which under
+        // `docker::container::merge_claude_code_settings` beats the global.
+        assert_eq!(stored.env_scrub, None);
+        assert_eq!(stored.auto_scroll_disabled, None);
+        assert_eq!(stored.focus_mode, None);
+        assert_eq!(stored.show_thinking_summaries, None);
+        assert_eq!(stored.prompt_caching_1h, None);
+        assert_eq!(stored.session_recap_disabled, None);
+        // A value the user did choose is untouched.
+        assert_eq!(stored.tui_mode.as_deref(), Some("fullscreen"));
+
+        // The merge rule itself, spelled the way
+        // `merge_claude_code_settings` spells it. `main` resolved this with
+        // `if p.env_scrub { true } else { g.env_scrub }`, i.e. the global won —
+        // and it has to go on winning, because the user never turned this off.
+        let global = ClaudeCodeSettings { env_scrub: Some(true), ..Default::default() };
+        assert_eq!(
+            stored.env_scrub.or(global.env_scrub),
+            Some(true),
+            "upgrading silently turned off 'strip credentials from subprocess environments'"
+        );
+    }
+
+    #[test]
+    fn an_off_chosen_in_the_new_editor_still_beats_a_global_on() {
+        // Same record without the pre-widening key: this `false` is the
+        // deliberate off the widening exists to make expressible.
+        let json = r#"{ "env_scrub": false }"#;
+        let chosen: ClaudeCodeSettings = serde_json::from_str(json).unwrap();
+        assert_eq!(chosen.env_scrub, Some(false));
+        let global = ClaudeCodeSettings { env_scrub: Some(true), ..Default::default() };
+        assert_eq!(chosen.env_scrub.or(global.env_scrub), Some(false));
+    }
+
+    #[test]
+    fn an_unset_setting_is_written_as_absent_rather_than_null() {
+        // A downgrade parses these fields as plain `bool` with
+        // `#[serde(default)]`: an absent key is `false`, a `null` is a parse
+        // error — and `ProjectsStore` parses all-or-nothing, so one project
+        // with one null empties the whole list and the next save persists that.
+        let json = serde_json::to_string(&ClaudeCodeSettings::default()).unwrap();
+        assert_eq!(json, "{}");
+        assert!(!json.contains("null"));
+
+        let partial = ClaudeCodeSettings { env_scrub: Some(false), ..Default::default() };
+        let json = serde_json::to_string(&partial).unwrap();
+        assert_eq!(json, r#"{"env_scrub":false}"#);
+        // And it reads back as what it is.
+        let round_tripped: ClaudeCodeSettings = serde_json::from_str(&json).unwrap();
+        assert_eq!(round_tripped, partial);
+    }
+
+    // ── The host-side per-project toggles ─────────────────────────────────
+
+    #[test]
+    fn a_project_stored_before_the_auth_bridge_existed_gets_it_turned_on() {
+        // The whole point of the serde default: `MAIN_SHAPE_PROJECT` is a real
+        // record written by a shipped binary and has no `auth_bridge_enabled`
+        // key at all. Without this, every existing project keeps hanging on
+        // `claude login` until its owner finds the toggle.
+        assert!(!MAIN_SHAPE_PROJECT.contains("auth_bridge_enabled"));
+        let project: Project = serde_json::from_str(MAIN_SHAPE_PROJECT).unwrap();
+        assert!(project.auth_bridge_enabled);
+
+        // The browser view is the other way round and must stay so: it costs a
+        // Node daemon, a container exec loop and a host port, and most
+        // containers have no Playwright to serve it with.
+        assert!(!project.browser_view_enabled);
+    }
+
+    #[test]
+    fn turning_the_auth_bridge_off_survives_the_default() {
+        // Opt-out has to be expressible, or the toggle does nothing across a
+        // restart. An explicit `false` in the file beats the default.
+        let json = r#"{ "auth_bridge_enabled": false }"#;
+        #[derive(Deserialize)]
+        struct JustTheFlag {
+            #[serde(default = "default_auth_bridge_enabled")]
+            auth_bridge_enabled: bool,
+        }
+        let parsed: JustTheFlag = serde_json::from_str(json).unwrap();
+        assert!(!parsed.auth_bridge_enabled);
+
+        // And a saved project always writes the key, so the choice is pinned
+        // rather than re-defaulted on the next load.
+        let mut p = Project::new("demo".to_string(), Vec::new());
+        p.auth_bridge_enabled = false;
+        let round_tripped: Project =
+            serde_json::from_str(&serde_json::to_string(&p).unwrap()).unwrap();
+        assert!(!round_tripped.auth_bridge_enabled);
+    }
+
+    #[test]
+    fn a_new_project_starts_with_the_bridge_on_and_the_view_off() {
+        let p = Project::new("demo".to_string(), Vec::new());
+        assert!(p.auth_bridge_enabled);
+        assert!(!p.browser_view_enabled);
+    }
+
+    #[test]
+    fn the_path_migration_never_writes_the_flags_and_so_cannot_defeat_the_default() {
+        // `ProjectsStore::new` runs every record through this before
+        // deserialising. If it inserted either key — even as `false` — the
+        // serde default above would never be consulted for an existing project
+        // and this change would be a no-op on exactly the projects it is for.
+        let legacy = serde_json::json!({
+            "id": "p1",
+            "name": "demo",
+            "path": "/home/u/demo",
+        });
+        let migrated = Project::migrate_from_value(legacy);
+        let obj = migrated.as_object().unwrap();
+        assert!(obj.contains_key("paths"), "the migration should still do its own job");
+        assert!(!obj.contains_key("auth_bridge_enabled"));
+        assert!(!obj.contains_key("browser_view_enabled"));
+    }
+}

app/src-tauri/src/models/settings_export.rs

@@ -0,0 +1,366 @@
+//! Settings export/import — see triple-c#35.
+//!
+//! `SettingsExportPayload` is the whole plaintext export before encryption
+//! and after decryption (see `storage::settings_crypto`). It bundles
+//! `AppSettings` — with one field carved out, see below — with the global
+//! secrets that live in the OS keychain instead: the shared Claude Code
+//! OAuth login and the model gateway's two keys. Per-project settings,
+//! per-project secrets, and anything living in a project's Docker volumes
+//! are deliberately out of scope: this exports the *host* environment, not
+//! any one project's.
+//!
+//! **`AppSettings` is not entirely the non-secret shape it looks like.**
+//! `WebTerminalSettings::access_token` is a live bearer credential for a
+//! server that binds every interface, stored as a plain field on the
+//! struct that is otherwise safe to treat as config. A review of this
+//! feature caught it: exporting `AppSettings` wholesale would have carried
+//! that token along as if it were as inert as a port number, and — worse —
+//! importing it would apply `web_terminal.enabled` and the token together
+//! with no more warning than any other setting, letting a crafted export
+//! silently stand up a LAN-listening terminal server with an
+//! attacker-known token on the next launch. `export_settings` /
+//! `apply_settings_import` blank this field out of the `settings` they
+//! read from and write to, and it travels only through
+//! [`ExportedSecrets::web_terminal_access_token`] instead, with the same
+//! "only overwrite what the import actually has" treatment as the other
+//! three secrets.
+
+use serde::{Deserialize, Serialize};
+
+use super::{AppSettings, ImageSource};
+
+/// Bumped when the shape of [`SettingsExportPayload`] changes in a way that
+/// isn't just an additive, `#[serde(default)]`-covered field — e.g. if a
+/// field is ever removed or its meaning changes. `apply_settings_import`
+/// checks this before touching anything.
+pub const SETTINGS_EXPORT_FORMAT_VERSION: u32 = 1;
+
+/// The global secrets bundled into an export. Deliberately a separate struct
+/// from `AppSettings`: these live in the OS keychain, never in
+/// `settings.json`, and — outside of this export/import flow — the values
+/// themselves never cross into the frontend; see the doc comments on
+/// `storage::secure::get_gateway_api_key` and
+/// `commands::settings_export_commands` for why that boundary matters here
+/// too.
+#[derive(Debug, Clone, Serialize, Deserialize, Default)]
+pub struct ExportedSecrets {
+    #[serde(default)]
+    pub claude_oauth_token: Option<String>,
+    #[serde(default)]
+    pub gateway_api_key: Option<String>,
+    #[serde(default)]
+    pub gateway_master_key: Option<String>,
+    /// See the module doc comment — this is `AppSettings::web_terminal
+    /// .access_token`, carved out because it is a live bearer credential,
+    /// not config, despite living on a struct that is otherwise safe to
+    /// export wholesale.
+    #[serde(default)]
+    pub web_terminal_access_token: Option<String>,
+}
+
+impl ExportedSecrets {
+    pub fn is_empty(&self) -> bool {
+        let blank = |s: &Option<String>| s.as_deref().is_none_or(|v| v.trim().is_empty());
+        blank(&self.claude_oauth_token)
+            && blank(&self.gateway_api_key)
+            && blank(&self.gateway_master_key)
+            && blank(&self.web_terminal_access_token)
+    }
+}
+
+/// What `apply_settings_import` hands back: the settings that were actually
+/// saved, plus a human-readable note for each keychain secret this import
+/// carried but could not be restored. A keychain write failing partway
+/// through must not read as unqualified success just because the settings
+/// half of the import went through.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct SettingsImportOutcome {
+    pub settings: AppSettings,
+    #[serde(default)]
+    pub secret_restore_warnings: Vec<String>,
+}
+
+/// The full plaintext payload — this is what gets encrypted on export and
+/// what decryption recovers on import. Never written to disk unencrypted;
+/// see `storage::settings_crypto`.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct SettingsExportPayload {
+    pub format_version: u32,
+    /// RFC3339. Purely informational — shown in the import preview so a user
+    /// picking between a few old export files has something to go on.
+    pub exported_at: String,
+    /// The exporting app's `CARGO_PKG_VERSION`. Also informational: every
+    /// field below already round-trips through `#[serde(default)]`-covered
+    /// `AppSettings`, so an older or newer export still deserializes; this is
+    /// for a human to notice "this is from a much older version" if an import
+    /// ever looks wrong, not something the code branches on.
+    pub app_version: String,
+    pub settings: AppSettings,
+    #[serde(default)]
+    pub secrets: ExportedSecrets,
+}
+
+/// What `preview_settings_import` hands the frontend before anything is
+/// applied — counts and presence flags only, **never** a secret value itself,
+/// so this type is safe to return across the IPC boundary and render
+/// directly. The confirmation UI is built from this.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct SettingsImportPreview {
+    pub exported_at: String,
+    pub app_version: String,
+    pub custom_env_var_count: usize,
+    pub gateway_model_count: usize,
+    pub has_claude_code_settings: bool,
+    pub has_claude_oauth_token: bool,
+    pub has_gateway_api_key: bool,
+    pub has_gateway_master_key: bool,
+    pub has_web_terminal_access_token: bool,
+    /// Whether the imported settings turn the web terminal on. Named
+    /// separately from the token above: `enabled` and the token are two
+    /// different fields, either can be true without the other, and
+    /// "this import turns on a service that listens on your network" is
+    /// exactly the kind of change a wholesale settings replace must not
+    /// bury in a generic "settings replaced" line — see the module doc
+    /// comment on why this field exists at all.
+    pub enables_web_terminal: bool,
+    /// Non-blank custom base URLs the import would set, so a redirect of
+    /// model traffic to somewhere other than the usual provider is visible
+    /// at import time rather than discovered later. These are endpoints, not
+    /// secrets — safe to show verbatim, unlike everything above.
+    #[serde(default)]
+    pub ollama_base_url: Option<String>,
+    #[serde(default)]
+    pub llamacpp_base_url: Option<String>,
+    #[serde(default)]
+    pub openai_compatible_base_url: Option<String>,
+    #[serde(default)]
+    pub gateway_api_base: Option<String>,
+    /// Whether the import sets a custom Docker image, and its name if so —
+    /// disclosed for the same reason as the base URLs above, and arguably
+    /// more sharply: this is the image *every* project container is created
+    /// from (`models::container_config::resolve_image_name`), so a crafted
+    /// export pointing it at an attacker-controlled image is a path to
+    /// running arbitrary code with whatever a project's containers are
+    /// allowed to reach (the Docker socket, an SSH key, project files) —
+    /// not merely a redirected API endpoint.
+    #[serde(default)]
+    pub image_source: ImageSource,
+    #[serde(default)]
+    pub custom_image_name: Option<String>,
+}
+
+/// A cap on how much of a decrypted, not-yet-trusted string gets echoed back
+/// into a preview a user reads and a UI renders without truncation of its
+/// own. Applied to every field above that carries free-form text straight
+/// from the import file rather than a count or a boolean — a base URL or an
+/// image name a hostile export author controls has had no validation done
+/// on it yet at preview time, and nothing stops it from being pathological
+/// (embedded control characters, or long enough to blow out the confirmation
+/// dialog and push the security warnings below it off screen).
+const MAX_PREVIEW_STRING_LEN: usize = 100;
+
+fn sanitize_for_preview(value: &str) -> String {
+    let cleaned: String = value.chars().filter(|c| !c.is_control()).collect();
+    let trimmed = cleaned.trim();
+    if trimmed.chars().count() > MAX_PREVIEW_STRING_LEN {
+        let truncated: String = trimmed.chars().take(MAX_PREVIEW_STRING_LEN).collect();
+        format!("{}…", truncated)
+    } else {
+        trimmed.to_string()
+    }
+}
+
+impl SettingsImportPreview {
+    pub fn from_payload(payload: &SettingsExportPayload) -> Self {
+        let non_blank = |s: &Option<String>| s.as_deref().is_some_and(|v| !v.trim().is_empty());
+        let sanitized_non_blank = |s: &Option<String>| {
+            s.as_deref()
+                .map(sanitize_for_preview)
+                .filter(|v| !v.is_empty())
+        };
+        Self {
+            exported_at: payload.exported_at.clone(),
+            app_version: payload.app_version.clone(),
+            custom_env_var_count: payload.settings.global_custom_env_vars.len(),
+            gateway_model_count: payload.settings.gateway.models.len(),
+            has_claude_code_settings: payload.settings.global_claude_code_settings.is_some(),
+            has_claude_oauth_token: non_blank(&payload.secrets.claude_oauth_token),
+            has_gateway_api_key: non_blank(&payload.secrets.gateway_api_key),
+            has_gateway_master_key: non_blank(&payload.secrets.gateway_master_key),
+            has_web_terminal_access_token: non_blank(&payload.secrets.web_terminal_access_token),
+            enables_web_terminal: payload.settings.web_terminal.enabled,
+            ollama_base_url: sanitized_non_blank(&payload.settings.global_ollama.base_url),
+            llamacpp_base_url: sanitized_non_blank(&payload.settings.global_llamacpp.base_url),
+            openai_compatible_base_url: sanitized_non_blank(
+                &payload.settings.global_openai_compatible.base_url,
+            ),
+            gateway_api_base: sanitized_non_blank(&payload.settings.gateway.api_base),
+            image_source: payload.settings.image_source.clone(),
+            custom_image_name: sanitized_non_blank(&payload.settings.custom_image_name),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::models::AppSettings;
+
+    fn payload_with(secrets: ExportedSecrets) -> SettingsExportPayload {
+        let settings = AppSettings {
+            global_custom_env_vars: vec![
+                crate::models::EnvVar {
+                    key: "A".to_string(),
+                    value: "1".to_string(),
+                },
+                crate::models::EnvVar {
+                    key: "B".to_string(),
+                    value: "2".to_string(),
+                },
+            ],
+            ..AppSettings::default()
+        };
+        SettingsExportPayload {
+            format_version: SETTINGS_EXPORT_FORMAT_VERSION,
+            exported_at: "2026-08-27T00:00:00Z".to_string(),
+            app_version: "0.4.14".to_string(),
+            settings,
+            secrets,
+        }
+    }
+
+    #[test]
+    fn the_preview_never_carries_a_secret_value() {
+        let payload = payload_with(ExportedSecrets {
+            claude_oauth_token: Some("sk-super-secret-token".to_string()),
+            gateway_api_key: Some("sk-another-secret".to_string()),
+            gateway_master_key: Some("sk-triple-c-yet-another".to_string()),
+            web_terminal_access_token: Some("wt-super-secret-token".to_string()),
+        });
+        let preview = SettingsImportPreview::from_payload(&payload);
+        let serialized = serde_json::to_string(&preview).unwrap();
+
+        assert!(!serialized.contains("sk-super-secret-token"));
+        assert!(!serialized.contains("sk-another-secret"));
+        assert!(!serialized.contains("sk-triple-c-yet-another"));
+        assert!(!serialized.contains("wt-super-secret-token"));
+        assert!(preview.has_claude_oauth_token);
+        assert!(preview.has_gateway_api_key);
+        assert!(preview.has_gateway_master_key);
+        assert!(preview.has_web_terminal_access_token);
+    }
+
+    #[test]
+    fn a_blank_secret_reads_as_absent_in_the_preview() {
+        // A keychain entry that exists but holds only whitespace must not
+        // read as "present" — same "blank counts as absent" rule the
+        // keychain layer itself applies when storing these.
+        let payload = payload_with(ExportedSecrets {
+            claude_oauth_token: Some("   ".to_string()),
+            gateway_api_key: None,
+            gateway_master_key: None,
+            web_terminal_access_token: Some("   ".to_string()),
+        });
+        let preview = SettingsImportPreview::from_payload(&payload);
+        assert!(!preview.has_claude_oauth_token);
+        assert!(!preview.has_gateway_api_key);
+        assert!(!preview.has_gateway_master_key);
+        assert!(!preview.has_web_terminal_access_token);
+    }
+
+    #[test]
+    fn enabling_the_web_terminal_is_surfaced_regardless_of_whether_a_token_came_with_it() {
+        // `enabled` and the token are independent fields — a crafted export
+        // could set one without the other, and both are worth a user's
+        // attention: this is the field that exists specifically so "this
+        // import turns on a service that listens on your network" cannot
+        // hide inside a generic "settings replaced" summary.
+        let mut payload = payload_with(ExportedSecrets::default());
+        payload.settings.web_terminal.enabled = true;
+        let preview = SettingsImportPreview::from_payload(&payload);
+        assert!(preview.enables_web_terminal);
+        assert!(!preview.has_web_terminal_access_token);
+    }
+
+    #[test]
+    fn custom_base_urls_are_surfaced_but_blank_ones_read_as_absent() {
+        let mut payload = payload_with(ExportedSecrets::default());
+        payload.settings.global_ollama.base_url = Some("http://attacker.example:11434".to_string());
+        payload.settings.global_llamacpp.base_url = Some("   ".to_string());
+        payload.settings.gateway.api_base = Some("https://gateway.example/v1".to_string());
+
+        let preview = SettingsImportPreview::from_payload(&payload);
+        assert_eq!(
+            preview.ollama_base_url.as_deref(),
+            Some("http://attacker.example:11434")
+        );
+        assert_eq!(preview.llamacpp_base_url, None);
+        assert_eq!(preview.openai_compatible_base_url, None);
+        assert_eq!(
+            preview.gateway_api_base.as_deref(),
+            Some("https://gateway.example/v1")
+        );
+    }
+
+    #[test]
+    fn counts_reflect_the_real_settings() {
+        let payload = payload_with(ExportedSecrets::default());
+        let preview = SettingsImportPreview::from_payload(&payload);
+        assert_eq!(preview.custom_env_var_count, 2);
+    }
+
+    #[test]
+    fn an_empty_secrets_bundle_reports_itself_as_empty() {
+        assert!(ExportedSecrets::default().is_empty());
+        assert!(!ExportedSecrets {
+            claude_oauth_token: Some("x".to_string()),
+            ..Default::default()
+        }
+        .is_empty());
+    }
+
+    #[test]
+    fn a_secrets_bundle_holding_only_whitespace_still_reports_itself_as_empty() {
+        // Matches the "blank counts as absent" rule every other consumer of
+        // these fields applies (`has_claude_oauth_token` and friends above) —
+        // a keychain entry that exists but holds only whitespace carries
+        // nothing usable, so the export-time "nothing to export" log line
+        // must still fire for it.
+        assert!(ExportedSecrets {
+            claude_oauth_token: Some("   ".to_string()),
+            ..Default::default()
+        }
+        .is_empty());
+    }
+
+    #[test]
+    fn a_custom_docker_image_is_surfaced() {
+        let mut payload = payload_with(ExportedSecrets::default());
+        payload.settings.image_source = crate::models::ImageSource::Custom;
+        payload.settings.custom_image_name = Some("ghcr.io/attacker/triple-c:latest".to_string());
+
+        let preview = SettingsImportPreview::from_payload(&payload);
+        assert_eq!(preview.image_source, crate::models::ImageSource::Custom);
+        assert_eq!(
+            preview.custom_image_name.as_deref(),
+            Some("ghcr.io/attacker/triple-c:latest")
+        );
+    }
+
+    #[test]
+    fn preview_strings_are_stripped_of_control_characters_and_capped_in_length() {
+        let mut payload = payload_with(ExportedSecrets::default());
+        payload.settings.global_ollama.base_url =
+            Some(format!("http://example.test/{}\u{0007}bell", "x".repeat(200)));
+
+        let preview = SettingsImportPreview::from_payload(&payload);
+        let shown = preview.ollama_base_url.expect("non-blank base url");
+        assert!(!shown.contains('\u{0007}'), "control character leaked into the preview");
+        // +1 for the trailing ellipsis appended when truncated.
+        assert!(
+            shown.chars().count() <= MAX_PREVIEW_STRING_LEN + 1,
+            "preview string was not capped: {} chars",
+            shown.chars().count()
+        );
+    }
+}

app/src-tauri/src/models/update_info.rs

@@ -26,6 +26,24 @@ pub struct GitHubRelease {
     pub body: String,
     pub assets: Vec<GitHubAsset>,
     pub published_at: String,
+    /// Whether GitHub itself has this release marked as a prerelease.
+    /// `#[serde(default)]` rather than required: every response GitHub sends
+    /// carries this, but nothing here should refuse to parse the rest of a
+    /// release over one missing field. Defaults to `false` (offered) rather
+    /// than `true` (excluded) — a missing field only happens if GitHub's API
+    /// shape changes, and "API changed, therefore updates silently stop
+    /// working forever" is the worse failure of the two.
+    ///
+    /// `build-app.yml`'s own mirror never publishes a prerelease, but
+    /// `.gitea/workflows/backfill-releases.yml` forwards every Gitea release
+    /// unfiltered, `prerelease` included. A preview release's `preview-<sha>`
+    /// tag already fails semver parsing on its own, so this field is not what
+    /// stops *that* case — it is what stops the case tag-parsing can't catch:
+    /// a normally-tagged release (`v0.4.13`) that someone marks as a
+    /// prerelease on Gitea (a hotfix candidate, an RC) and a backfill then
+    /// mirrors as-is. Real defence for that case, not a no-op.
+    #[serde(default)]
+    pub prerelease: bool,
 }
 
 /// GitHub API asset response (internal).

app/src-tauri/src/storage/mod.rs

@@ -1,6 +1,9 @@
 pub mod migration_store;
+pub mod notes_store;
+pub mod pending_cleanup;
 pub mod projects_store;
 pub mod secure;
+pub mod settings_crypto;
 pub mod settings_store;
 
 #[allow(unused_imports)]

app/src-tauri/src/storage/notes_store.rs

@@ -0,0 +1,593 @@
+//! Host-side persistence for per-project notes.
+//!
+//! One JSON file per project under `<data_dir>/triple-c/notes/`, on the same
+//! free-function shape as `migration_store` — no struct, nothing in
+//! `AppState`, no in-memory copy. `ProjectsStore` holds a `Mutex` because it
+//! caches the project list; a store that reads and writes the file per call
+//! has nothing to cache and nothing to guard.
+//!
+//! Deliberately *not* a field on `Project`. `projects.json` is rewritten on
+//! every blur by the debounced-nothing save path in `useSaveState`, so notes
+//! there would mean the whole project list is rewritten per edit, and a note
+//! save racing a Config save would silently drop one of them.
+
+use std::fs;
+use std::path::{Path, PathBuf};
+use std::sync::{Mutex, OnceLock};
+
+use serde::{Deserialize, Serialize};
+
+use crate::models::Note;
+
+/// The version stamped into every notes file this build writes.
+const NOTES_FORMAT_VERSION: u32 = 1;
+
+/// What is actually on disk: a version envelope around the notes.
+///
+/// The list is wrapped rather than written bare because the wrapper costs
+/// nothing today and cannot be added cheaply later — once files exist in the
+/// field, every reader has to sniff two shapes forever. `version` is written
+/// and read back but nothing branches on it yet: it is the hook a future
+/// format change hangs off, and its value is only useful if it has been there
+/// since the first file.
+///
+/// Not in `models/` and not exposed over IPC: the frontend receives
+/// `Vec<Note>` from `list_notes` and never sees the envelope, so this is a
+/// storage detail rather than part of the IPC contract.
+#[derive(Debug, Serialize, Deserialize)]
+struct ProjectNotes {
+    version: u32,
+    #[serde(default)]
+    notes: Vec<Note>,
+}
+
+/// Serialises the read-modify-write half of an upsert or delete.
+///
+/// Nothing here is cached, so there is no shared state to protect — but an
+/// upsert reads the whole file, edits one entry and writes it back, and two of
+/// those interleaving would lose whichever note was written first. The read
+/// path does not take it.
+fn write_lock() -> &'static Mutex<()> {
+    static LOCK: OnceLock<Mutex<()>> = OnceLock::new();
+    LOCK.get_or_init(|| Mutex::new(()))
+}
+
+/// `<data_dir>/triple-c/notes`, created on demand.
+pub fn notes_dir() -> Result<PathBuf, String> {
+    let dir = dirs::data_dir()
+        .ok_or_else(|| {
+            "Could not determine data directory. Set XDG_DATA_HOME on Linux.".to_string()
+        })?
+        .join("triple-c")
+        .join("notes");
+    fs::create_dir_all(&dir).map_err(|e| format!("Failed to create notes directory: {}", e))?;
+    Ok(dir)
+}
+
+/// Project ids are UUIDs, but they arrive over IPC, so refuse to let one steer
+/// the write anywhere but the notes directory.
+fn sanitize(project_id: &str) -> String {
+    project_id
+        .chars()
+        .map(|c| if c.is_ascii_alphanumeric() || c == '-' || c == '_' { c } else { '_' })
+        .collect()
+}
+
+fn notes_path_in(dir: &Path, project_id: &str) -> PathBuf {
+    dir.join(format!("{}.json", sanitize(project_id)))
+}
+
+// ── Public API. Each resolves the real directory, then defers to the `_in`
+// variant, which is what the tests exercise against a temp dir. `ProjectsStore`
+// hardcodes `dirs::data_dir()` in its constructor and is therefore untestable
+// as a unit; this store does not inherit that. ─────────────────────────────
+
+pub fn load(project_id: &str) -> Result<Vec<Note>, String> {
+    load_in(&notes_dir()?, project_id)
+}
+
+pub fn upsert(project_id: &str, note: Note) -> Result<Note, String> {
+    upsert_in(&notes_dir()?, project_id, note)
+}
+
+pub fn delete(project_id: &str, note_id: &str) -> Result<(), String> {
+    delete_in(&notes_dir()?, project_id, note_id)
+}
+
+/// Remove a project's notes file entirely. Missing is success.
+pub fn clear(project_id: &str) -> Result<(), String> {
+    clear_in(&notes_dir()?, project_id)
+}
+
+// ── Implementation ─────────────────────────────────────────────────────────
+
+/// Read a project's notes. A missing file is an empty list.
+///
+/// **An unparseable file is copied aside and left in place**, then reported as
+/// empty. Erroring instead would make the Notes tab permanently unusable for
+/// that project with no way out through the UI; deleting instead would destroy
+/// the only copy of what the user wrote. The copy is timestamped so a second
+/// corruption cannot overwrite the first — which is the one taken before
+/// anything rewrote the file, and therefore the one worth having — and capped,
+/// because `list_notes` runs on *every* panel mount. See [`keep_corrupt_copy`].
+fn load_in(dir: &Path, project_id: &str) -> Result<Vec<Note>, String> {
+    let path = notes_path_in(dir, project_id);
+    if !path.exists() {
+        return Ok(Vec::new());
+    }
+    let data = fs::read_to_string(&path).map_err(|e| format!("Failed to read notes: {}", e))?;
+    match parse(&data) {
+        Ok(notes) => Ok(notes),
+        Err(e) => {
+            let kept = keep_corrupt_copy(&path, &chrono::Utc::now());
+            log::error!(
+                "Failed to parse notes for project {}: {} — treating as empty; the file is \
+                 left in place{}",
+                project_id,
+                e,
+                kept.describe()
+            );
+            Ok(Vec::new())
+        }
+    }
+}
+
+/// Parse a notes file: the versioned envelope, or a bare array.
+///
+/// The bare array is what this store wrote before [`ProjectNotes`] existed —
+/// only ever on a development build, but a developer's own notes are still
+/// prose nothing else holds a copy of, and the alternative is `load_in`
+/// declaring a perfectly readable file corrupt. It is read, never written: the
+/// first save rewrites the file with an envelope.
+fn parse(data: &str) -> Result<Vec<Note>, serde_json::Error> {
+    match serde_json::from_str::<ProjectNotes>(data) {
+        Ok(file) => Ok(file.notes),
+        // Report the envelope's error, not the array's — the envelope is the
+        // shape this store writes, so its message is the one that describes
+        // what is actually wrong with the file.
+        Err(envelope_err) => serde_json::from_str::<Vec<Note>>(data).map_err(|_| envelope_err),
+    }
+}
+
+/// How many timestamped copies of one project's corrupt notes file are kept.
+///
+/// Timestamping fixes "a second corruption overwrote the first" and introduces
+/// its opposite: `load_in` runs on every `list_notes`, which is every panel
+/// mount — every project switch, every dock-follows-tab change, every sub-tab
+/// toggle. A file that is *persistently* unparseable (the normal case, since
+/// nothing repairs it) would otherwise mint a fresh full copy of the user's
+/// prose every time the clock's second changed. Nothing ever reads them back
+/// and nothing ever removed them.
+///
+/// Four is enough for the only use there is: a human looking at what the file
+/// held. Same constant, same reasoning as `migration_store`.
+const MAX_CORRUPT_BACKUPS: usize = 4;
+
+/// What [`keep_corrupt_copy`] did, so the log line can tell the truth about
+/// whether a file exists.
+///
+/// Three outcomes, and they must not be conflated. Folding "already kept
+/// enough" into success and then saying "a copy was kept" names a file that
+/// was never created — which is what someone reads before going to look for
+/// their data.
+enum Kept {
+    Copied(PathBuf),
+    /// This exact second's copy was already on disk.
+    AlreadyThere(PathBuf),
+    /// The cap is reached; the earlier copies are kept and this one is not.
+    EnoughAlready(usize),
+    Failed(String),
+}
+
+impl Kept {
+    fn describe(&self) -> String {
+        match self {
+            Kept::Copied(p) | Kept::AlreadyThere(p) => format!(" (a copy is at {})", p.display()),
+            // The earliest copies are the ones worth having, so the cap keeps
+            // those and drops this one. Say so, rather than implying a file
+            // exists.
+            Kept::EnoughAlready(n) => format!(
+                " (no copy kept — {} earlier copies of this file are already saved alongside it)",
+                n
+            ),
+            Kept::Failed(e) => format!(" (could not keep a copy: {})", e),
+        }
+    }
+}
+
+/// Where a copy of an unreadable notes file is kept.
+fn corrupt_backup_path(path: &Path, now: &chrono::DateTime<chrono::Utc>) -> PathBuf {
+    path.with_extension(format!("json.corrupt-{}.bak", now.format("%Y%m%d-%H%M%S")))
+}
+
+/// Whether [`MAX_CORRUPT_BACKUPS`] copies of this project's file already exist.
+///
+/// Asked *before* the copy rather than pruning after it, so the cap is not
+/// implemented by writing a file and deleting it again on every pass — and so
+/// the copies that survive are the oldest, which are the ones taken closest to
+/// whatever produced the corruption.
+///
+/// A directory that cannot be listed answers "not full": failing open costs at
+/// most one extra file, and failing closed would drop the very first copy of
+/// prose nothing else has kept.
+fn corrupt_backups_full(path: &Path) -> bool {
+    let (Some(dir), Some(stem)) = (path.parent(), path.file_stem()) else {
+        return false;
+    };
+    // `{stem}.json.corrupt-` — the same shape `corrupt_backup_path` builds, so
+    // this can never match another project's copies or an unrelated `.bak`.
+    let prefix = format!("{}.json.corrupt-", stem.to_string_lossy());
+    let Ok(entries) = fs::read_dir(dir) else {
+        return false;
+    };
+    entries
+        .flatten()
+        .filter(|e| {
+            let name = e.file_name().to_string_lossy().to_string();
+            name.starts_with(&prefix) && name.ends_with(".bak")
+        })
+        .count()
+        >= MAX_CORRUPT_BACKUPS
+}
+
+fn keep_corrupt_copy(path: &Path, now: &chrono::DateTime<chrono::Utc>) -> Kept {
+    let backup = corrupt_backup_path(path, now);
+    if backup.exists() {
+        return Kept::AlreadyThere(backup);
+    }
+    if corrupt_backups_full(path) {
+        return Kept::EnoughAlready(MAX_CORRUPT_BACKUPS);
+    }
+    match fs::copy(path, &backup) {
+        Ok(_) => Kept::Copied(backup),
+        Err(e) => Kept::Failed(e.to_string()),
+    }
+}
+
+/// Insert or replace one note, leaving the rest untouched.
+///
+/// `created_at` and `id` are the store's, not the caller's: the webview sends
+/// a whole `Note` back and must not be able to rewrite when a note was made.
+/// `updated_at` is stamped here for the same reason.
+fn upsert_in(dir: &Path, project_id: &str, mut note: Note) -> Result<Note, String> {
+    let _guard = write_lock().lock().unwrap_or_else(|e| e.into_inner());
+    let mut notes = load_in(dir, project_id)?;
+    note.updated_at = chrono::Utc::now().to_rfc3339();
+    match notes.iter_mut().find(|n| n.id == note.id) {
+        Some(existing) => {
+            note.created_at = existing.created_at.clone();
+            *existing = note.clone();
+        }
+        None => notes.push(note.clone()),
+    }
+    save_all(dir, project_id, &notes)?;
+    Ok(note)
+}
+
+/// Remove one note. Removing one that is already gone is success — the UI can
+/// retry a delete whose result it never saw.
+fn delete_in(dir: &Path, project_id: &str, note_id: &str) -> Result<(), String> {
+    let _guard = write_lock().lock().unwrap_or_else(|e| e.into_inner());
+    let mut notes = load_in(dir, project_id)?;
+    let before = notes.len();
+    notes.retain(|n| n.id != note_id);
+    if notes.len() == before {
+        return Ok(());
+    }
+    save_all(dir, project_id, &notes)
+}
+
+fn clear_in(dir: &Path, project_id: &str) -> Result<(), String> {
+    let _guard = write_lock().lock().unwrap_or_else(|e| e.into_inner());
+    let path = notes_path_in(dir, project_id);
+    match fs::remove_file(&path) {
+        Ok(()) => Ok(()),
+        Err(e) if e.kind() == std::io::ErrorKind::NotFound => Ok(()),
+        Err(e) => Err(format!("Failed to remove notes: {}", e)),
+    }
+}
+
+/// Atomically **and durably** write the whole list.
+///
+/// Write-temp-then-rename alone is only half of it. `fs::write` returns once
+/// the bytes are in the page cache; the rename is atomic with respect to other
+/// readers, not to power loss. Losing power in that window leaves the rename
+/// applied and the data not written — a truncated file, produced by the code
+/// whose job is to prevent one. So the file is fsynced before the rename and
+/// the directory after it, since the rename is directory metadata. Notes are
+/// prose the user typed and nothing else holds a copy.
+fn save_all(dir: &Path, project_id: &str, notes: &[Note]) -> Result<(), String> {
+    let path = notes_path_in(dir, project_id);
+    let file = ProjectNotes {
+        version: NOTES_FORMAT_VERSION,
+        notes: notes.to_vec(),
+    };
+    let data = serde_json::to_string_pretty(&file)
+        .map_err(|e| format!("Failed to serialize notes: {}", e))?;
+    let tmp = path.with_extension("json.tmp");
+
+    {
+        use std::io::Write;
+        let mut file =
+            fs::File::create(&tmp).map_err(|e| format!("Failed to write notes: {}", e))?;
+        file.write_all(data.as_bytes())
+            .map_err(|e| format!("Failed to write notes: {}", e))?;
+        file.sync_all()
+            .map_err(|e| format!("Failed to flush notes to disk: {}", e))?;
+    }
+
+    fs::rename(&tmp, &path).map_err(|e| format!("Failed to commit notes: {}", e))?;
+    sync_dir(&path);
+    Ok(())
+}
+
+/// fsync the directory holding `path`, so the rename survives power loss.
+///
+/// Best effort only where it is meaningless: Windows has no directory handle
+/// to sync and returns an error for the attempt, so a failure is logged rather
+/// than propagated. The file's own `sync_all` carries the data and is not best
+/// effort.
+fn sync_dir(path: &Path) {
+    let Some(dir) = path.parent() else { return };
+    if let Err(e) = fs::File::open(dir).and_then(|d| d.sync_all()) {
+        log::debug!(
+            "Could not fsync the notes directory {}: {} — the file itself was flushed",
+            dir.display(),
+            e
+        );
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn temp_dir(tag: &str) -> std::path::PathBuf {
+        let dir = std::env::temp_dir().join(format!(
+            "triple-c-notes-{}-{}",
+            tag,
+            uuid::Uuid::new_v4().simple()
+        ));
+        std::fs::create_dir_all(&dir).expect("temp dir");
+        dir
+    }
+
+    fn corrupt_copies(dir: &std::path::Path) -> Vec<String> {
+        std::fs::read_dir(dir)
+            .unwrap()
+            .flatten()
+            .map(|e| e.file_name().to_string_lossy().to_string())
+            .filter(|n| n.contains(".corrupt-"))
+            .collect()
+    }
+
+    #[test]
+    fn project_ids_cannot_escape_the_notes_directory() {
+        // The id arrives over IPC. It must not be able to steer the write.
+        assert_eq!(sanitize("../../etc/passwd"), "______etc_passwd");
+        assert_eq!(sanitize("a/b"), "a_b");
+        assert_eq!(sanitize("a\\b"), "a_b");
+        // A real UUID must survive untouched, or every note file would move
+        // the first time this function changed.
+        assert_eq!(
+            sanitize("ab62cd24-51aa-4645-8f5c-17a124062050"),
+            "ab62cd24-51aa-4645-8f5c-17a124062050"
+        );
+    }
+
+    #[test]
+    fn a_missing_file_is_an_empty_list_not_an_error() {
+        let dir = temp_dir("missing");
+        assert_eq!(load_in(&dir, "nobody").unwrap(), Vec::<Note>::new());
+        std::fs::remove_dir_all(&dir).ok();
+    }
+
+    #[test]
+    fn an_upserted_note_round_trips() {
+        let dir = temp_dir("roundtrip");
+        let note = Note::new("Deploy steps".into(), "one\ntwo".into());
+        let saved = upsert_in(&dir, "p1", note.clone()).unwrap();
+        assert_eq!(saved.id, note.id);
+
+        let loaded = load_in(&dir, "p1").unwrap();
+        assert_eq!(loaded.len(), 1);
+        assert_eq!(loaded[0].body, "one\ntwo");
+        std::fs::remove_dir_all(&dir).ok();
+    }
+
+    #[test]
+    fn upserting_an_existing_id_replaces_it_and_keeps_created_at() {
+        let dir = temp_dir("replace");
+        let mut note = Note::new("Title".into(), "first".into());
+        upsert_in(&dir, "p1", note.clone()).unwrap();
+
+        note.body = "second".into();
+        note.created_at = "1999-01-01T00:00:00Z".into(); // a client must not rewrite this
+        let saved = upsert_in(&dir, "p1", note.clone()).unwrap();
+
+        let loaded = load_in(&dir, "p1").unwrap();
+        assert_eq!(loaded.len(), 1, "an upsert must not append a duplicate");
+        assert_eq!(loaded[0].body, "second");
+        assert_ne!(
+            saved.created_at, "1999-01-01T00:00:00Z",
+            "created_at is owned by the store, not by whatever the webview sent"
+        );
+        std::fs::remove_dir_all(&dir).ok();
+    }
+
+    #[test]
+    fn deleting_a_note_leaves_the_others_and_a_missing_one_is_success() {
+        let dir = temp_dir("delete");
+        let keep = upsert_in(&dir, "p1", Note::new("keep".into(), "".into())).unwrap();
+        let drop = upsert_in(&dir, "p1", Note::new("drop".into(), "".into())).unwrap();
+
+        delete_in(&dir, "p1", &drop.id).unwrap();
+        let loaded = load_in(&dir, "p1").unwrap();
+        assert_eq!(loaded.len(), 1);
+        assert_eq!(loaded[0].id, keep.id);
+
+        // Idempotent: removing what is already gone is not an error, because
+        // the UI can retry a delete it never saw the result of.
+        delete_in(&dir, "p1", &drop.id).unwrap();
+        std::fs::remove_dir_all(&dir).ok();
+    }
+
+    #[test]
+    fn an_unreadable_file_is_copied_aside_and_reads_as_empty() {
+        // Same reasoning as migration_store: a corrupt file must not make the
+        // tab permanently unusable, and the bytes must not be destroyed.
+        let dir = temp_dir("corrupt");
+        let path = notes_path_in(&dir, "p1");
+        std::fs::write(&path, b"{ not json").unwrap();
+
+        assert_eq!(load_in(&dir, "p1").unwrap(), Vec::<Note>::new());
+        assert!(path.exists(), "the unreadable file is left in place");
+
+        assert_eq!(
+            corrupt_copies(&dir).len(),
+            1,
+            "the bytes must be kept exactly once"
+        );
+        std::fs::remove_dir_all(&dir).ok();
+    }
+
+    #[test]
+    fn what_is_written_is_a_version_envelope_not_a_bare_array() {
+        // The envelope costs nothing now and cannot be added cheaply once
+        // files exist in the field, so the very first file has to carry it.
+        let dir = temp_dir("envelope");
+        upsert_in(&dir, "p1", Note::new("t".into(), "b".into())).unwrap();
+
+        let raw = std::fs::read_to_string(notes_path_in(&dir, "p1")).unwrap();
+        let parsed: serde_json::Value = serde_json::from_str(&raw).unwrap();
+        assert_eq!(parsed["version"], NOTES_FORMAT_VERSION);
+        assert_eq!(parsed["notes"].as_array().unwrap().len(), 1);
+        assert_eq!(parsed["notes"][0]["body"], "b");
+        std::fs::remove_dir_all(&dir).ok();
+    }
+
+    #[test]
+    fn a_pre_envelope_bare_array_still_reads_and_is_not_called_corrupt() {
+        // Only a development build ever wrote this shape, but declaring a
+        // perfectly readable file corrupt is the one outcome this store exists
+        // to avoid. It is read, never written back.
+        let dir = temp_dir("legacy");
+        let note = Note::new("Deploy".into(), "one\ntwo".into());
+        std::fs::write(
+            notes_path_in(&dir, "p1"),
+            serde_json::to_string(&vec![note.clone()]).unwrap(),
+        )
+        .unwrap();
+
+        let loaded = load_in(&dir, "p1").unwrap();
+        assert_eq!(loaded.len(), 1);
+        assert_eq!(loaded[0].body, "one\ntwo");
+        let copies = corrupt_copies(&dir);
+        assert!(copies.is_empty(), "a readable file must not be copied aside");
+
+        // The next write upgrades it in place.
+        upsert_in(&dir, "p1", note).unwrap();
+        let raw = std::fs::read_to_string(notes_path_in(&dir, "p1")).unwrap();
+        assert!(raw.contains("\"version\""));
+        std::fs::remove_dir_all(&dir).ok();
+    }
+
+    #[test]
+    fn corrupt_copies_are_capped_rather_than_one_per_second() {
+        // `list_notes` runs on every panel mount, so an unrepaired file would
+        // otherwise mint a full copy of the user's prose every time the
+        // clock's second changed.
+        let dir = temp_dir("cap");
+        let path = notes_path_in(&dir, "p1");
+        std::fs::write(&path, b"{ not json").unwrap();
+
+        let base = chrono::Utc::now();
+        for i in 0..MAX_CORRUPT_BACKUPS as i64 + 3 {
+            let at = base + chrono::Duration::seconds(i);
+            let kept = keep_corrupt_copy(&path, &at);
+            if i < MAX_CORRUPT_BACKUPS as i64 {
+                assert!(matches!(kept, Kept::Copied(_)), "copy {} should be kept", i);
+            } else {
+                assert!(
+                    matches!(kept, Kept::EnoughAlready(MAX_CORRUPT_BACKUPS)),
+                    "copy {} should be refused by the cap",
+                    i
+                );
+            }
+        }
+        assert_eq!(corrupt_copies(&dir).len(), MAX_CORRUPT_BACKUPS);
+        std::fs::remove_dir_all(&dir).ok();
+    }
+
+    #[test]
+    fn a_second_read_in_the_same_second_does_not_re_copy() {
+        let dir = temp_dir("samesecond");
+        let path = notes_path_in(&dir, "p1");
+        std::fs::write(&path, b"{ not json").unwrap();
+
+        let at = chrono::Utc::now();
+        assert!(matches!(keep_corrupt_copy(&path, &at), Kept::Copied(_)));
+        assert!(matches!(
+            keep_corrupt_copy(&path, &at),
+            Kept::AlreadyThere(_)
+        ));
+        assert_eq!(corrupt_copies(&dir).len(), 1);
+        std::fs::remove_dir_all(&dir).ok();
+    }
+
+    #[test]
+    fn the_log_line_never_claims_a_backup_that_was_not_written() {
+        // A message that invents a backup is worse than no message: it is what
+        // someone reads before going to look for their data.
+        let dir = temp_dir("honesty");
+        let path = notes_path_in(&dir, "p1");
+        std::fs::write(&path, b"{ not json").unwrap();
+
+        let copied = keep_corrupt_copy(&path, &chrono::Utc::now()).describe();
+        assert!(copied.contains("a copy is at"));
+
+        let refused = Kept::EnoughAlready(MAX_CORRUPT_BACKUPS).describe();
+        assert!(refused.contains("no copy kept"));
+        assert!(!refused.contains("a copy is at"));
+
+        let failed = Kept::Failed("permission denied".into()).describe();
+        assert!(failed.contains("could not keep a copy"));
+        assert!(!failed.contains("a copy is at"));
+        std::fs::remove_dir_all(&dir).ok();
+    }
+
+    #[test]
+    fn a_write_leaves_no_temp_file_behind() {
+        let dir = temp_dir("tmp");
+        upsert_in(&dir, "p1", Note::new("t".into(), "b".into())).unwrap();
+        let leftovers: Vec<_> = std::fs::read_dir(&dir)
+            .unwrap()
+            .flatten()
+            .filter(|e| e.file_name().to_string_lossy().ends_with(".tmp"))
+            .collect();
+        assert!(leftovers.is_empty(), "the rename must have consumed the temp file");
+        std::fs::remove_dir_all(&dir).ok();
+    }
+
+    #[test]
+    fn clearing_a_project_removes_its_file_and_missing_is_success() {
+        let dir = temp_dir("clear");
+        upsert_in(&dir, "p1", Note::new("t".into(), "b".into())).unwrap();
+        assert!(notes_path_in(&dir, "p1").exists());
+
+        clear_in(&dir, "p1").unwrap();
+        assert!(!notes_path_in(&dir, "p1").exists());
+        clear_in(&dir, "p1").unwrap(); // idempotent
+        std::fs::remove_dir_all(&dir).ok();
+    }
+
+    #[test]
+    fn clearing_is_what_project_removal_calls_and_it_never_fails_on_absence() {
+        // `remove_project` must not be able to fail because a project simply
+        // never had any notes — an orphaned notes file is harmless, a project
+        // that cannot be removed is not.
+        let dir = temp_dir("removal");
+        assert!(clear_in(&dir, "never-had-notes").is_ok());
+        std::fs::remove_dir_all(&dir).ok();
+    }
+}

app/src-tauri/src/storage/pending_cleanup.rs

@@ -0,0 +1,349 @@
+//! Host-side record of Docker resources `remove_project` could not delete.
+//!
+//! `remove_project` drops a project's id from `projects.json` unconditionally
+//! — see the comment on `ProjectRemovalReport` — so once that happens nothing
+//! in the app can name the leftover container, image or volume again by any
+//! path a user can reach. This is what keeps it reachable anyway: one JSON
+//! file per affected project under `<data_dir>/triple-c/pending-cleanup/`,
+//! written *before* the project record is dropped. Startup housekeeping
+//! retries every record on the next launch (see
+//! `commands::project_commands::retry_pending_cleanup_logged`) and deletes
+//! the ones that fully succeed.
+//!
+//! **This record is written in the same instant its record in `projects.json`
+//! is destroyed, and it is the only remaining handle on the leftover
+//! resource** — which is a stronger claim on durability than an ordinary
+//! write-temp-then-rename gives. `storage::migration_store::save` carries the
+//! same reasoning for the migration state file: `fs::write` returns once the
+//! bytes are in the page cache, and a rename over them is atomic with respect
+//! to other readers, not to power loss. A crash in that window leaves the
+//! rename applied and the data half-written, which [`list`] then treats as
+//! unparseable and skips — reproducing the exact bug this module exists to
+//! close, silently, with only a startup log line as evidence. So `save` here
+//! takes the same `File::create` → `write_all` → `sync_all` → `rename` →
+//! directory-sync shape `migration_store` does.
+
+use std::fs;
+use std::path::{Path, PathBuf};
+
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct PendingCleanup {
+    pub project_id: String,
+    /// Kept only so a log line or a future UI can name the project without a
+    /// second lookup — the project record itself is already gone by the time
+    /// this is read back.
+    pub project_name: String,
+    /// The project's container, if it could not be removed. Named by its
+    /// deterministic `triple-c-{id}` name rather than the (possibly stale)
+    /// container id Docker handed out — Docker's remove-container API
+    /// accepts either, and the name is the one identifier guaranteed to still
+    /// resolve to the same container by the time a retry runs.
+    pub container_id: Option<String>,
+    pub image: Option<String>,
+    pub volumes: Vec<String>,
+    pub recorded_at: String,
+}
+
+impl PendingCleanup {
+    /// True once nothing named here still needs to be removed.
+    pub fn is_empty(&self) -> bool {
+        self.container_id.is_none() && self.image.is_none() && self.volumes.is_empty()
+    }
+}
+
+/// `<data_dir>/triple-c/pending-cleanup`, created on demand.
+fn dir() -> Result<PathBuf, String> {
+    let dir = dirs::data_dir()
+        .ok_or_else(|| {
+            "Could not determine data directory. Set XDG_DATA_HOME on Linux.".to_string()
+        })?
+        .join("triple-c")
+        .join("pending-cleanup");
+    fs::create_dir_all(&dir)
+        .map_err(|e| format!("Failed to create pending-cleanup directory: {}", e))?;
+    Ok(dir)
+}
+
+/// Project ids are UUIDs, but they arrive over IPC, so refuse to let one steer
+/// the write anywhere but the pending-cleanup directory. Mirrors
+/// `storage::migration_store::sanitize`.
+fn sanitize(project_id: &str) -> String {
+    project_id
+        .chars()
+        .map(|c| if c.is_ascii_alphanumeric() || c == '-' || c == '_' { c } else { '_' })
+        .collect()
+}
+
+/// Write (or overwrite) a project's pending-cleanup record.
+pub fn save(record: &PendingCleanup) -> Result<(), String> {
+    save_in(&dir()?, record)
+}
+
+/// Remove a project's pending-cleanup record. Missing is success — this is
+/// how a fully-succeeded retry (or a record that never existed) is expressed.
+pub fn clear(project_id: &str) -> Result<(), String> {
+    clear_in(&dir()?, project_id)
+}
+
+/// Every pending-cleanup record on disk. An unparseable file is logged and
+/// skipped rather than blocking every other project's retry — the same
+/// "one bad record can't wedge the rest" reasoning as the migration store.
+pub fn list() -> Vec<PendingCleanup> {
+    let Ok(dir) = dir() else { return Vec::new() };
+    list_in(&dir)
+}
+
+fn path_in(dir: &Path, project_id: &str) -> PathBuf {
+    dir.join(format!("{}.json", sanitize(project_id)))
+}
+
+/// Durable write: fsync the file before the rename, and fsync the directory
+/// after it — see the module doc comment for why a plain
+/// write-temp-then-rename is not enough here. Mirrors
+/// `storage::migration_store::save`/`sync_dir`.
+fn save_in(dir: &Path, record: &PendingCleanup) -> Result<(), String> {
+    let path = path_in(dir, &record.project_id);
+    let data = serde_json::to_string_pretty(record)
+        .map_err(|e| format!("Failed to serialize pending cleanup record: {}", e))?;
+    let tmp = path.with_extension("json.tmp");
+
+    {
+        use std::io::Write;
+        let mut file = fs::File::create(&tmp)
+            .map_err(|e| format!("Failed to write pending cleanup record: {}", e))?;
+        file.write_all(data.as_bytes())
+            .map_err(|e| format!("Failed to write pending cleanup record: {}", e))?;
+        file.sync_all()
+            .map_err(|e| format!("Failed to flush pending cleanup record to disk: {}", e))?;
+    }
+
+    fs::rename(&tmp, &path)
+        .map_err(|e| format!("Failed to commit pending cleanup record: {}", e))?;
+    sync_dir(&path);
+    Ok(())
+}
+
+fn clear_in(dir: &Path, project_id: &str) -> Result<(), String> {
+    let path = path_in(dir, project_id);
+    match fs::remove_file(&path) {
+        Ok(()) => Ok(()),
+        Err(e) if e.kind() == std::io::ErrorKind::NotFound => Ok(()),
+        Err(e) => Err(format!("Failed to remove pending cleanup record: {}", e)),
+    }
+}
+
+fn list_in(dir: &Path) -> Vec<PendingCleanup> {
+    let Ok(entries) = fs::read_dir(dir) else { return Vec::new() };
+
+    entries
+        .flatten()
+        .filter(|e| e.path().extension().is_some_and(|ext| ext == "json"))
+        .filter_map(|e| {
+            let path = e.path();
+            let data = fs::read_to_string(&path).ok()?;
+            match serde_json::from_str::<PendingCleanup>(&data) {
+                Ok(record) => Some(record),
+                Err(err) => {
+                    // Moved aside rather than left in place: a record nothing
+                    // ever repairs would otherwise warn on every single
+                    // startup forever, same as an ordinary `.json` file it
+                    // would keep looking like one to `list_in` on the next
+                    // call too. One aside-copy is enough here — this only
+                    // ever holds names to retry removing, not the class of
+                    // once-in-a-lifetime crash evidence `migration_store`
+                    // keeps multiple timestamped backups of.
+                    let corrupt = path.with_extension("json.corrupt");
+                    let moved = !corrupt.exists() && fs::rename(&path, &corrupt).is_ok();
+                    log::warn!(
+                        "Could not parse pending cleanup record {}: {}{}",
+                        path.display(),
+                        err,
+                        if moved {
+                            format!(" — moved aside to {}", corrupt.display())
+                        } else {
+                            " — leaving it in place".to_string()
+                        }
+                    );
+                    None
+                }
+            }
+        })
+        .collect()
+}
+
+/// fsync the directory holding `path`, so a rename into it survives power
+/// loss. Best effort only on the platforms where it is meaningless: Windows
+/// has no directory handle to sync and errors on the attempt, so failure is
+/// logged rather than propagated — the file's own `sync_all` above is what
+/// carries the data. Mirrors `storage::migration_store::sync_dir`, which is
+/// private to that module, so this is a small deliberate duplicate rather
+/// than a shared dependency between two otherwise-independent stores.
+fn sync_dir(path: &Path) {
+    let Some(dir) = path.parent() else { return };
+    match fs::File::open(dir).and_then(|d| d.sync_all()) {
+        Ok(()) => {}
+        Err(e) => log::debug!(
+            "Could not fsync the pending-cleanup directory {}: {} — the record itself was flushed",
+            dir.display(),
+            e
+        ),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn temp_dir(name: &str) -> PathBuf {
+        let dir = std::env::temp_dir().join(format!(
+            "triple-c-pending-cleanup-{}-{}",
+            name,
+            uuid::Uuid::new_v4().simple()
+        ));
+        fs::create_dir_all(&dir).unwrap();
+        dir
+    }
+
+    fn record(project_id: &str) -> PendingCleanup {
+        PendingCleanup {
+            project_id: project_id.to_string(),
+            project_name: "Some Project".to_string(),
+            container_id: Some("triple-c-abc".to_string()),
+            image: Some("triple-c-snapshot-abc:latest".to_string()),
+            volumes: vec!["triple-c-home-abc".to_string()],
+            recorded_at: "2026-08-25T00:00:00Z".to_string(),
+        }
+    }
+
+    #[test]
+    fn project_ids_cannot_escape_the_pending_cleanup_directory() {
+        assert_eq!(sanitize("../../etc/passwd"), "______etc_passwd");
+        assert_eq!(sanitize("a/b"), "a_b");
+        assert_eq!(
+            sanitize("ab62cd24-51aa-4645-8f5c-17a124062050"),
+            "ab62cd24-51aa-4645-8f5c-17a124062050"
+        );
+    }
+
+    #[test]
+    fn is_empty_reflects_whatever_still_needs_removing() {
+        let mut r = record("p1");
+        assert!(!r.is_empty());
+
+        r.container_id = None;
+        r.image = None;
+        assert!(!r.is_empty(), "a leftover volume alone still counts");
+
+        r.volumes.clear();
+        assert!(r.is_empty());
+    }
+
+    /// Exercises the real `save_in`/`list_in`/`clear_in` — not a
+    /// re-implementation of their bodies — against a temp directory standing
+    /// in for `dir()`.
+    #[test]
+    fn a_saved_record_round_trips_and_clearing_removes_it() {
+        let dir = temp_dir("roundtrip");
+        let rec = record("proj-1");
+
+        save_in(&dir, &rec).expect("save");
+        let found = list_in(&dir);
+        assert_eq!(found.len(), 1);
+        assert_eq!(found[0].project_id, "proj-1");
+        assert_eq!(found[0].volumes, vec!["triple-c-home-abc".to_string()]);
+
+        clear_in(&dir, "proj-1").expect("clear");
+        assert!(list_in(&dir).is_empty());
+
+        fs::remove_dir_all(&dir).ok();
+    }
+
+    /// A second `save` for the same project overwrites rather than appending
+    /// — a retry that narrows the leftovers must not leave the old, wider
+    /// record behind it.
+    #[test]
+    fn saving_the_same_project_twice_overwrites_not_appends() {
+        let dir = temp_dir("overwrite");
+        let mut rec = record("proj-1");
+        save_in(&dir, &rec).expect("save");
+
+        rec.container_id = None;
+        rec.image = None;
+        save_in(&dir, &rec).expect("save again");
+
+        let found = list_in(&dir);
+        assert_eq!(found.len(), 1, "one file per project, not one per save");
+        assert!(found[0].container_id.is_none());
+        assert_eq!(found[0].volumes, vec!["triple-c-home-abc".to_string()]);
+
+        fs::remove_dir_all(&dir).ok();
+    }
+
+    /// A record that fails to parse must not poison the rest of the listing.
+    #[test]
+    fn an_unparseable_record_is_skipped_not_fatal() {
+        let dir = temp_dir("corrupt");
+        fs::write(dir.join("bad.json"), "{ not json").unwrap();
+        save_in(&dir, &record("proj-2")).expect("save");
+
+        let found = list_in(&dir);
+        assert_eq!(found.len(), 1);
+        assert_eq!(found[0].project_id, "proj-2");
+
+        fs::remove_dir_all(&dir).ok();
+    }
+
+    /// A record that fails to parse is moved aside once, rather than left in
+    /// place to be re-warned about — and re-warned about — on every future
+    /// launch forever.
+    #[test]
+    fn an_unparseable_record_is_moved_aside_exactly_once() {
+        let dir = temp_dir("corrupt-aside");
+        let bad = dir.join("bad.json");
+        fs::write(&bad, "{ not json").unwrap();
+
+        list_in(&dir);
+        assert!(!bad.exists(), "the bad file should have been moved aside");
+        let corrupt = dir.join("bad.json.corrupt");
+        assert!(corrupt.exists(), "and the moved copy should be at .json.corrupt");
+
+        // A second pass must not warn about `bad.json` again — it is gone —
+        // and must not choke on `.json.corrupt` already being there.
+        assert!(list_in(&dir).is_empty());
+        assert!(corrupt.exists(), "the aside copy is not itself deleted");
+
+        fs::remove_dir_all(&dir).ok();
+    }
+
+    /// `list_in` must not pick up the `.json.tmp` staging file `save_in`
+    /// leaves behind if a crash lands between the write and the rename — the
+    /// whole point of the temp-then-rename dance is that only the renamed
+    /// file is ever a complete record.
+    #[test]
+    fn a_leftover_tmp_file_is_not_listed() {
+        let dir = temp_dir("tmp-leftover");
+        fs::write(dir.join("proj-3.json.tmp"), "not a complete record").unwrap();
+        assert!(list_in(&dir).is_empty());
+
+        fs::remove_dir_all(&dir).ok();
+    }
+
+    /// Clearing by project id must remove exactly the file that id maps to
+    /// under `sanitize`, and nothing else.
+    #[test]
+    fn clearing_one_project_does_not_touch_another() {
+        let dir = temp_dir("clear-scoped");
+        save_in(&dir, &record("proj-a")).unwrap();
+        save_in(&dir, &record("proj-b")).unwrap();
+
+        clear_in(&dir, "proj-a").unwrap();
+
+        let found = list_in(&dir);
+        assert_eq!(found.len(), 1);
+        assert_eq!(found[0].project_id, "proj-b");
+
+        fs::remove_dir_all(&dir).ok();
+    }
+}

app/src-tauri/src/storage/projects_store.rs

@@ -241,6 +241,21 @@ impl ProjectsStore {
         }
     }
 
+    /// Granular setter for the browser view's opt-in, for the same reason
+    /// [`Self::set_auth_bridge_enabled`] has one: the pane toggles this while
+    /// the Config tab may be holding an older copy of the whole record.
+    pub fn set_browser_view_enabled(&self, project_id: &str, enabled: bool) -> Result<(), String> {
+        let mut projects = self.lock();
+        if let Some(p) = projects.iter_mut().find(|p| p.id == project_id) {
+            p.browser_view_enabled = enabled;
+            p.updated_at = chrono::Utc::now().to_rfc3339();
+            self.save(&projects)?;
+            Ok(())
+        } else {
+            Err(format!("Project {} not found", project_id))
+        }
+    }
+
     pub fn set_container_id(&self, project_id: &str, container_id: Option<String>) -> Result<(), String> {
         let mut projects = self.lock();
         if let Some(p) = projects.iter_mut().find(|p| p.id == project_id) {
@@ -338,4 +353,61 @@ mod tests {
 
         fs::remove_dir_all(&dir).ok();
     }
+
+    /// A store over a temp file. `new()` insists on `dirs::data_dir()`, which
+    /// is the real user's; the fields are right here, so the granular setters
+    /// can be exercised against a directory the test owns.
+    fn store_over(dir: &Path, projects: Vec<Project>) -> ProjectsStore {
+        ProjectsStore {
+            projects: Mutex::new(projects),
+            file_path: dir.join("projects.json"),
+        }
+    }
+
+    #[test]
+    fn the_browser_view_flag_is_written_to_disk_and_read_back() {
+        // The point of the whole exercise: before this the flag lived in a
+        // `HashSet` in `BrowserViewManager` and an app restart forgot it.
+        let dir = temp_dir("browser-view");
+        let project = Project::new("demo".to_string(), Vec::new());
+        let id = project.id.clone();
+        let store = store_over(&dir, vec![project]);
+
+        assert!(!store.get(&id).unwrap().browser_view_enabled);
+        store.set_browser_view_enabled(&id, true).unwrap();
+        assert!(store.get(&id).unwrap().browser_view_enabled);
+
+        // Durable, not merely in memory — this is what a restart reads.
+        let on_disk: Vec<Project> =
+            serde_json::from_str(&fs::read_to_string(dir.join("projects.json")).unwrap()).unwrap();
+        assert!(on_disk[0].browser_view_enabled);
+
+        store.set_browser_view_enabled(&id, false).unwrap();
+        assert!(!store.get(&id).unwrap().browser_view_enabled);
+
+        assert!(store.set_browser_view_enabled("no-such-project", true).is_err());
+
+        fs::remove_dir_all(&dir).ok();
+    }
+
+    #[test]
+    fn a_granular_toggle_leaves_every_other_field_alone() {
+        // Why these setters exist at all: the Config tab can be holding an
+        // older copy of the whole record while the pane flips one flag.
+        let dir = temp_dir("granular");
+        let mut project = Project::new("demo".to_string(), Vec::new());
+        project.claude_instructions = Some("keep me".to_string());
+        let id = project.id.clone();
+        let store = store_over(&dir, vec![project]);
+
+        store.set_browser_view_enabled(&id, true).unwrap();
+        store.set_auth_bridge_enabled(&id, false).unwrap();
+
+        let saved = store.get(&id).unwrap();
+        assert_eq!(saved.claude_instructions.as_deref(), Some("keep me"));
+        assert!(saved.browser_view_enabled);
+        assert!(!saved.auth_bridge_enabled);
+
+        fs::remove_dir_all(&dir).ok();
+    }
 }

app/src-tauri/src/storage/secure.rs

@@ -321,28 +321,52 @@ pub fn delete_gateway_api_key() -> Result<(), String> {
 /// only enforces auth when a master key is configured, so Triple-C always
 /// configures one.
 pub fn get_or_create_gateway_master_key() -> Result<String, String> {
-    if let Some(existing) = read_entry(GATEWAY_MASTER_KEY_SERVICE, "the gateway master key")? {
-        if !existing.trim().is_empty() {
-            return Ok(existing);
-        }
+    if let Some(existing) = get_gateway_master_key()? {
+        return Ok(existing);
     }
     regenerate_gateway_master_key()
 }
 
+/// Read the gateway master key without minting one if none exists yet.
+/// Distinct from [`get_or_create_gateway_master_key`], which mints as a side
+/// effect the read half of that function must not have — settings export
+/// (triple-c#35) needs "is there one, and if so what is it", not "make sure
+/// one exists".
+pub fn get_gateway_master_key() -> Result<Option<String>, String> {
+    Ok(read_entry(GATEWAY_MASTER_KEY_SERVICE, "the gateway master key")?
+        .filter(|k| !k.trim().is_empty()))
+}
+
 /// Mint a new gateway master key, invalidating the old one. Projects using the
 /// previous value must be updated.
 pub fn regenerate_gateway_master_key() -> Result<String, String> {
     // LiteLLM requires the master key to start with `sk-`.
     let key = format!("sk-triple-c-{}", uuid::Uuid::new_v4().simple());
+    store_gateway_master_key(&key)?;
+    Ok(key)
+}
+
+/// Store an exact given gateway master key, replacing any previous one.
+///
+/// Distinct from [`regenerate_gateway_master_key`], which always mints a
+/// fresh random value: this exists for settings import (triple-c#35), where
+/// restoring the *same* key an export captured is the point — projects on
+/// the destination machine may not exist yet, but a project migrated or
+/// re-added later that still has the old key pasted into its config must
+/// keep working against it. Blank input is rejected rather than silently
+/// stored, matching every other `store_*` function in this module.
+pub fn store_gateway_master_key(key: &str) -> Result<(), String> {
+    if key.trim().is_empty() {
+        return Err("Refusing to store an empty gateway master key.".to_string());
+    }
 
     let entry = keyring::Entry::new(GATEWAY_MASTER_KEY_SERVICE, KEYCHAIN_ACCOUNT)
         .map_err(|e| format!("Keyring error: {}", e))?;
     entry
-        .set_password(&key)
+        .set_password(key.trim())
         .map_err(|e| format!("Failed to store the gateway master key: {}", e))?;
 
-    bump_gateway_secret_version()?;
-    Ok(key)
+    bump_gateway_secret_version()
 }
 
 

app/src-tauri/src/storage/settings_crypto.rs

@@ -0,0 +1,184 @@
+//! Password-based encryption for the settings export/import file — see
+//! triple-c#35.
+//!
+//! The exported payload can carry live credentials (the shared Claude OAuth
+//! token, the gateway provider/master keys — see
+//! `commands::settings_export_commands`), so this is not encryption for its
+//! own sake; a wrong or missing key here is a real credential leak, not a
+//! cosmetic bug. Argon2id derives a 256-bit key from the password (memory-
+//! hard, meaningfully resistant to GPU/ASIC brute-forcing in a way PBKDF2 at
+//! any reasonable iteration count is not), and AES-256-GCM is what actually
+//! encrypts — authenticated, so a wrong password is detected by a failed tag
+//! check rather than producing silent garbage.
+//!
+//! File format: `MAGIC (4 bytes) | salt (16 bytes) | nonce (12 bytes) |
+//! ciphertext+tag`. The salt and nonce are not secret — they are written in
+//! the clear right here, on purpose. The salt's only job is to make two
+//! exports with the same password derive different keys (defeats a
+//! precomputed-table attack against the password alone); the nonce's job is
+//! GCM's requirement that a (key, nonce) pair never repeat. Both hold
+//! because a fresh random value is drawn for each, on every call to
+//! [`encrypt`].
+//!
+//! The whole header (magic + salt + nonce) is passed to AES-GCM as
+//! associated data, not just placed alongside the ciphertext — free to do,
+//! and it makes tampering with any header byte fail the same authentication
+//! check the ciphertext gets, by construction rather than as a side effect
+//! of the salt/nonce also feeding key derivation and the cipher.
+
+use aes_gcm::aead::{Aead, KeyInit, Payload};
+use aes_gcm::{Aes256Gcm, Nonce};
+use argon2::{Algorithm, Argon2, Params, Version};
+use rand::RngCore;
+use zeroize::Zeroizing;
+
+/// Identifies the file as a Triple-C settings export and pins the format —
+/// a change to the salt/nonce lengths or the KDF/cipher choice below needs a
+/// new magic value, not a silent reinterpretation of old bytes.
+const MAGIC: &[u8; 4] = b"TCX1";
+const SALT_LEN: usize = 16;
+const NONCE_LEN: usize = 12;
+const KEY_LEN: usize = 32;
+const HEADER_LEN: usize = MAGIC.len() + SALT_LEN + NONCE_LEN;
+
+/// Argon2id parameters: memory cost in KiB, time cost (iterations),
+/// parallelism. `(19 MiB, 2, 1)` is OWASP's documented minimum recommendation
+/// for Argon2id — deliberately heavier than a login-flow KDF would use, since
+/// this runs once per export/import rather than on every request, so trading
+/// roughly a second of wall time for real brute-force resistance costs
+/// nothing a user would notice.
+fn argon2_params() -> Params {
+    Params::new(19 * 1024, 2, 1, Some(KEY_LEN)).expect("hardcoded Argon2 params are valid")
+}
+
+/// The derived key is wrapped in `Zeroizing` so it is overwritten with zeros
+/// when it drops rather than left in freed memory for whatever reuses that
+/// stack slot next — cheap insurance (`zeroize` is already in the dependency
+/// tree via `aes-gcm`) for material that exists only to decrypt live
+/// credentials.
+fn derive_key(password: &str, salt: &[u8]) -> Result<Zeroizing<[u8; KEY_LEN]>, String> {
+    let argon2 = Argon2::new(Algorithm::Argon2id, Version::V0x13, argon2_params());
+    let mut key = Zeroizing::new([0u8; KEY_LEN]);
+    argon2
+        .hash_password_into(password.as_bytes(), salt, &mut *key)
+        .map_err(|e| format!("Failed to derive encryption key: {}", e))?;
+    Ok(key)
+}
+
+/// Encrypt `plaintext` with a key derived from `password`. Returns the whole
+/// file's bytes (header + ciphertext) — see the module doc for the layout.
+pub fn encrypt(plaintext: &[u8], password: &str) -> Result<Vec<u8>, String> {
+    let mut salt = [0u8; SALT_LEN];
+    rand::rng().fill_bytes(&mut salt);
+    let key = derive_key(password, &salt)?;
+
+    let mut nonce_bytes = [0u8; NONCE_LEN];
+    rand::rng().fill_bytes(&mut nonce_bytes);
+    let nonce = Nonce::from_slice(&nonce_bytes);
+
+    let mut header = Vec::with_capacity(HEADER_LEN);
+    header.extend_from_slice(MAGIC);
+    header.extend_from_slice(&salt);
+    header.extend_from_slice(&nonce_bytes);
+
+    let cipher = Aes256Gcm::new_from_slice(&*key)
+        .map_err(|e| format!("Failed to initialize cipher: {}", e))?;
+    // The header (magic + salt + nonce) is authenticated as associated data
+    // even though none of it is secret: it costs nothing extra here, and it
+    // means tampering with any header byte is caught by the same tag check
+    // that already covers the ciphertext, by construction rather than as a
+    // side effect of the header also feeding key/nonce derivation.
+    let ciphertext = cipher
+        .encrypt(nonce, Payload { msg: plaintext, aad: &header })
+        .map_err(|e| format!("Encryption failed: {}", e))?;
+
+    let mut out = header;
+    out.extend_from_slice(&ciphertext);
+    Ok(out)
+}
+
+/// Decrypt a file produced by [`encrypt`]. The one error this returns for a
+/// wrong password is deliberately generic ("wrong password, or the file is
+/// corrupted") rather than distinguishing the two: GCM's authentication tag
+/// fails to verify for the wrong key on essentially any ciphertext, so there
+/// is no reliable way to tell "wrong password" from "corrupted file" apart,
+/// and guessing would be worse than saying so.
+///
+/// Returns `Zeroizing<Vec<u8>>` rather than a plain `Vec<u8>` — the plaintext
+/// this recovers is the whole settings-plus-secrets payload, so it gets the
+/// same "wipe it when it drops" treatment as the derived key in
+/// [`derive_key`].
+pub fn decrypt(data: &[u8], password: &str) -> Result<Zeroizing<Vec<u8>>, String> {
+    if data.len() < HEADER_LEN {
+        return Err("This does not look like a Triple-C settings export (file too short).".to_string());
+    }
+    if &data[..MAGIC.len()] != MAGIC {
+        return Err("This does not look like a Triple-C settings export (unrecognized file).".to_string());
+    }
+    let header = &data[..HEADER_LEN];
+    let salt = &data[MAGIC.len()..MAGIC.len() + SALT_LEN];
+    let nonce_bytes = &data[MAGIC.len() + SALT_LEN..HEADER_LEN];
+    let ciphertext = &data[HEADER_LEN..];
+
+    let key = derive_key(password, salt)?;
+    let cipher = Aes256Gcm::new_from_slice(&*key)
+        .map_err(|e| format!("Failed to initialize cipher: {}", e))?;
+    let nonce = Nonce::from_slice(nonce_bytes);
+    cipher
+        .decrypt(nonce, Payload { msg: ciphertext, aad: header })
+        .map(Zeroizing::new)
+        .map_err(|_| "Wrong password, or the file is corrupted.".to_string())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn a_round_trip_with_the_right_password_recovers_the_plaintext() {
+        let plaintext = b"{\"settings\": \"whatever\"}";
+        let encrypted = encrypt(plaintext, "correct horse battery staple").unwrap();
+        let decrypted = decrypt(&encrypted, "correct horse battery staple").unwrap();
+        assert_eq!(&*decrypted, plaintext);
+    }
+
+    #[test]
+    fn the_wrong_password_fails_rather_than_returning_garbage() {
+        let encrypted = encrypt(b"secret payload", "correct password").unwrap();
+        let result = decrypt(&encrypted, "wrong password");
+        assert!(result.is_err(), "decrypting with the wrong password must fail, not silently succeed");
+    }
+
+    #[test]
+    fn two_exports_of_the_same_plaintext_and_password_produce_different_files() {
+        // If this ever failed it would mean the salt or nonce stopped being
+        // randomized — either one repeating is a real security regression
+        // (a fixed salt lets an attacker precompute against the password
+        // alone; a repeated (key, nonce) pair breaks GCM's guarantees
+        // outright), not just a cosmetic one.
+        let a = encrypt(b"same plaintext", "same password").unwrap();
+        let b = encrypt(b"same plaintext", "same password").unwrap();
+        assert_ne!(a, b, "two independent exports must not be byte-identical");
+    }
+
+    #[test]
+    fn corrupting_a_single_byte_of_ciphertext_is_detected() {
+        let mut encrypted = encrypt(b"tamper-evident payload", "a password").unwrap();
+        let last = encrypted.len() - 1;
+        encrypted[last] ^= 0xFF;
+        assert!(decrypt(&encrypted, "a password").is_err());
+    }
+
+    #[test]
+    fn a_file_that_is_too_short_is_rejected_cleanly_not_by_panicking() {
+        assert!(decrypt(b"short", "any password").is_err());
+        assert!(decrypt(b"", "any password").is_err());
+    }
+
+    #[test]
+    fn a_file_with_the_wrong_magic_is_rejected() {
+        let mut encrypted = encrypt(b"payload", "password").unwrap();
+        encrypted[0] = b'X';
+        assert!(decrypt(&encrypted, "password").is_err());
+    }
+}

app/src-tauri/src/url_open.rs

@@ -0,0 +1,791 @@
+//! Opening a URL in the *host's* browser — the half of triple-c#34 where
+//! "Open" appeared to do nothing on Linux.
+//!
+//! # Why this module exists rather than `openUrl` from `@tauri-apps/plugin-opener`
+//!
+//! The plugin's Linux path shells out to `xdg-open`, and the child inherits
+//! this process's environment verbatim. Inside an AppImage that environment is
+//! not the user's — it is the AppImage's, and it is actively hostile to any
+//! program that is not the one the bundle was built for:
+//!
+//!  - linuxdeploy's `AppRun`/`AppRun.wrapped` prepends the bundle's own
+//!    directories to `LD_LIBRARY_PATH`, `PATH`, `XDG_DATA_DIRS`, `PYTHONPATH`,
+//!    `PERLLIB`, `QT_PLUGIN_PATH` and `GSETTINGS_SCHEMA_DIR`.
+//!  - `linuxdeploy-plugin-gtk`'s hook adds `GTK_PATH`, `GTK_EXE_PREFIX`,
+//!    `GTK_DATA_PREFIX`, `GTK_IM_MODULE_FILE`, `GIO_MODULE_DIR` and
+//!    `GDK_PIXBUF_MODULE_FILE`.
+//!  - `scripts/finalize-appimage.sh` installs one more hook of our own
+//!    (`triple-c-wayland-fallback.sh`) that can prepend
+//!    `$APPDIR/usr/lib/wayland-fallback` to `LD_LIBRARY_PATH`.
+//!  - `main.rs` sets `WEBKIT_DISABLE_DMABUF_RENDERER` process-wide, and the
+//!    comment there has flagged this leak for a while: it reaches whatever the
+//!    app spawns afterwards.
+//!
+//! A browser that is *already running* is unaffected — `xdg-open` just hands
+//! the URL to the existing instance over D-Bus/IPC and the new process exits.
+//! A **cold-launched** browser loads our bundled GTK/glib/pixbuf stack against
+//! the host's, aborts before it ever paints, and `xdg-open` has already
+//! returned 0. From the app's point of view the click did nothing. That is the
+//! reported symptom, and it is why the bug only reproduces for some people.
+//!
+//! # What this does instead
+//!
+//! `open_url_external` re-validates the URL (see below) and spawns the opener
+//! with a **sanitized child environment**. Sanitizing is
+//! [`sanitize_child_env`], a pure function over two maps so it can be tested
+//! without touching process-wide state:
+//!
+//!  1. If the AppImage saved the pre-launch value under a `*_ORIG` /
+//!     `APPIMAGE_ORIGINAL_*` name, restore that. Restoring a saved original is
+//!     strictly better than unsetting, because the user may genuinely have had
+//!     an `LD_LIBRARY_PATH` of their own.
+//!  2. Otherwise, if the variable differs from the value this process started
+//!     with, restore the start-up value. That is what undoes *our own*
+//!     `std::env::set_var` — `main.rs` snapshots the environment via
+//!     [`capture_pristine_environment`] before any mutation runs.
+//!  3. Otherwise, drop only the entries that point inside `$APPDIR`, keeping
+//!     the rest of the list intact. Blanket-unsetting would also discard
+//!     whatever the user's session had set; this removes exactly the
+//!     bundle's own contribution.
+//!
+//! Nothing is invented: a variable the pristine environment did not have and
+//! that does not point into `$APPDIR` is left alone, so outside an AppImage
+//! (`cargo tauri dev`, a distro build) this is very close to a no-op.
+//!
+//! # Portal vs. `xdg-open`
+//!
+//! `org.freedesktop.portal.OpenURI` would sidestep both the environment leak
+//! *and* a missing `x-scheme-handler/https` association, but reaching it means
+//! a D-Bus client — `zbus` and its async stack — as a new dependency for one
+//! call, on the only platform where we ship a single self-contained binary.
+//! It also only helps where a portal is running, which is precisely the
+//! desktop-environment case in which `xdg-open` already works once the
+//! environment is clean. The environment *is* the bug here, so the cheap fix
+//! is the complete one. `gio open` is kept as a second candidate because it
+//! goes through GIO's own handler lookup rather than `xdg-open`'s shell
+//! heuristics, which covers most of what the portal would have covered.
+//!
+//! # Security
+//!
+//! The URL reaching this command originates in an **untrusted container** (see
+//! `app/src/lib/urlRelay.ts`). The frontend validates with `sanitizeRelayUrl`,
+//! but a compromised webview can call this command directly, so the rules are
+//! mirrored here and enforced again: `http`/`https` only, a non-empty host, no
+//! embedded credentials, no control characters or whitespace, and a length
+//! cap. The URL is never passed through a shell — `std::process::Command` with
+//! explicit arguments, so there is no word-splitting, no globbing and no
+//! metacharacter to escape.
+
+use std::collections::BTreeMap;
+use std::sync::OnceLock;
+
+use url::Url;
+
+/// Hard cap on a URL we will hand to the OS. Mirrors `MAX_RELAY_URL_LENGTH`
+/// in `app/src/lib/urlRelay.ts`.
+const MAX_URL_LEN: usize = 8192;
+
+/// The environment this process was started with, captured before anything
+/// mutates it. See [`capture_pristine_environment`].
+// Only the Linux spawn path reads these; the macOS/Windows path delegates to
+// the opener plugin. Kept unconditional (rather than `#[cfg(linux)]`) so the
+// tests and the documentation stay in one piece on every platform.
+#[cfg_attr(not(target_os = "linux"), allow(dead_code))]
+static PRISTINE_ENV: OnceLock<BTreeMap<String, String>> = OnceLock::new();
+
+/// Record the environment as it was at process start.
+///
+/// Must be called from `main()` **before** any `std::env::set_var` — today
+/// that means before `apply_webkit_wayland_workaround()`, which is the only
+/// mutation in the tree. Calling it twice is harmless; the first call wins.
+///
+/// This is the only reliable source of truth for "what did the user actually
+/// have?" for variables *we* set. It cannot recover what `AppRun` overwrote
+/// before `main()` ran — that is what the `*_ORIG` and `$APPDIR` rules in
+/// [`sanitize_child_env`] are for.
+pub fn capture_pristine_environment() {
+    let _ = PRISTINE_ENV.set(std::env::vars().collect());
+}
+
+/// Variables an AppImage launcher is known to override, and that break a
+/// cold-launched child that is not this app.
+///
+/// `PATH` is in the list for the same reason as the rest: `AppRun` prepends
+/// `$APPDIR/usr/bin`, and resolving `xdg-open` (or anything the browser's own
+/// wrapper script calls) out of the bundle is its own failure mode.
+// Only the Linux spawn path reads these; the macOS/Windows path delegates to
+// the opener plugin. Kept unconditional (rather than `#[cfg(linux)]`) so the
+// tests and the documentation stay in one piece on every platform.
+#[cfg_attr(not(target_os = "linux"), allow(dead_code))]
+const SANITIZED_VARS: &[&str] = &[
+    "GDK_PIXBUF_MODULEDIR",
+    "GDK_PIXBUF_MODULE_FILE",
+    "GIO_MODULE_DIR",
+    "GSETTINGS_SCHEMA_DIR",
+    "GTK_DATA_PREFIX",
+    "GTK_EXE_PREFIX",
+    "GTK_IM_MODULE_FILE",
+    "GTK_PATH",
+    "LD_LIBRARY_PATH",
+    "PATH",
+    "PERLLIB",
+    "PYTHONPATH",
+    "QT_PLUGIN_PATH",
+    "XDG_DATA_DIRS",
+    // Set by `main.rs`, not by AppRun — rule 2 (the pristine snapshot) is what
+    // removes it, since the pristine environment almost never has it.
+    "WEBKIT_DISABLE_DMABUF_RENDERER",
+];
+
+/// What to do to one variable in the child: `Some(value)` sets it, `None`
+/// removes it.
+// Only the Linux spawn path reads these; the macOS/Windows path delegates to
+// the opener plugin. Kept unconditional (rather than `#[cfg(linux)]`) so the
+// tests and the documentation stay in one piece on every platform.
+#[cfg_attr(not(target_os = "linux"), allow(dead_code))]
+type EnvChange = (String, Option<String>);
+
+/// True when `entry` is `appdir` itself or a path inside it.
+// Only the Linux spawn path reads these; the macOS/Windows path delegates to
+// the opener plugin. Kept unconditional (rather than `#[cfg(linux)]`) so the
+// tests and the documentation stay in one piece on every platform.
+#[cfg_attr(not(target_os = "linux"), allow(dead_code))]
+fn is_inside(entry: &str, appdir: &str) -> bool {
+    let appdir = appdir.trim_end_matches('/');
+    if appdir.is_empty() {
+        return false;
+    }
+    entry == appdir || entry.strip_prefix(appdir).is_some_and(|r| r.starts_with('/'))
+}
+
+/// Drop the `$APPDIR` entries from a colon-separated list, keeping order and
+/// keeping everything else.
+///
+/// Single-valued variables (`GDK_PIXBUF_MODULE_FILE`, say) are just lists of
+/// one, so they need no separate case: a value inside `$APPDIR` filters down
+/// to nothing and the variable is removed.
+// Only the Linux spawn path reads these; the macOS/Windows path delegates to
+// the opener plugin. Kept unconditional (rather than `#[cfg(linux)]`) so the
+// tests and the documentation stay in one piece on every platform.
+#[cfg_attr(not(target_os = "linux"), allow(dead_code))]
+fn strip_appdir_entries(value: &str, appdir: &str) -> Option<String> {
+    let kept: Vec<&str> = value
+        .split(':')
+        .filter(|entry| !entry.is_empty() && !is_inside(entry, appdir))
+        .collect();
+    if kept.is_empty() {
+        None
+    } else {
+        Some(kept.join(":"))
+    }
+}
+
+/// Compute the changes that turn `current` into an environment safe to hand a
+/// cold-launched host program.
+///
+/// Pure on purpose — `current` and `pristine` are passed in rather than read
+/// from the process, so the rules can be tested without a global mutex around
+/// the environment. Returns changes sorted by variable name so assertions are
+/// deterministic.
+// Only the Linux spawn path reads these; the macOS/Windows path delegates to
+// the opener plugin. Kept unconditional (rather than `#[cfg(linux)]`) so the
+// tests and the documentation stay in one piece on every platform.
+#[cfg_attr(not(target_os = "linux"), allow(dead_code))]
+fn sanitize_child_env(
+    current: &BTreeMap<String, String>,
+    pristine: &BTreeMap<String, String>,
+    appdir: Option<&str>,
+) -> Vec<EnvChange> {
+    let mut changes: Vec<EnvChange> = Vec::new();
+
+    for var in SANITIZED_VARS {
+        let now = current.get(*var);
+
+        // 1. A saved original always wins. Both spellings are checked because
+        //    which one exists depends on the launcher: linuxdeploy's AppRun
+        //    and the various `AppRun.wrapped` generations have used each.
+        //    An empty saved value means "it was unset", not "set it to empty".
+        let saved = current
+            .get(&format!("{var}_ORIG"))
+            .or_else(|| current.get(&format!("APPIMAGE_ORIGINAL_{var}")));
+        if let Some(saved) = saved {
+            let restored = if saved.is_empty() {
+                None
+            } else {
+                Some(saved.clone())
+            };
+            if restored.as_ref() != now {
+                changes.push((var.to_string(), restored));
+            }
+            continue;
+        }
+
+        // 2. We changed it ourselves after start-up — put back what was there.
+        let at_start = pristine.get(*var);
+        if at_start != now {
+            changes.push((var.to_string(), at_start.cloned()));
+            continue;
+        }
+
+        // 3. Polluted before `main()` ran, with nothing saved. Remove the
+        //    bundle's own entries and keep the user's.
+        let (Some(now), Some(appdir)) = (now, appdir) else {
+            continue;
+        };
+        let stripped = strip_appdir_entries(now, appdir);
+        if stripped.as_deref() != Some(now.as_str()) {
+            changes.push((var.to_string(), stripped));
+        }
+    }
+
+    changes.sort_by(|a, b| a.0.cmp(&b.0));
+    changes
+}
+
+/// Whether `candidate` holds a character that disqualifies it before parsing.
+///
+/// Mirrors `hasForbiddenChar` in `app/src/lib/urlRelay.ts`, and for the same
+/// reasons: C0/C1 controls and whitespace are invisible in the UI and are
+/// stripped rather than rejected by some URL parsers, and quote characters are
+/// illegal in a URL per RFC 3986 while being exactly what an argument-splitting
+/// opener downstream would act on. Written as a scan over code points rather
+/// than a regex so the control ranges cannot be mangled by an editing tool.
+fn has_forbidden_char(candidate: &str) -> bool {
+    candidate.chars().any(|ch| {
+        let code = ch as u32;
+        code <= 0x20
+            || code == 0x7f
+            || (0x80..=0x9f).contains(&code)
+            || ch == '"'
+            || ch == '\''
+            || ch == '`'
+            || ch.is_whitespace()
+    })
+}
+
+/// Validate a URL an untrusted source asked the host to open.
+///
+/// Returns the normalized URL, or a message safe to show the user. The message
+/// never echoes the input: it is the input that is untrusted, and this error
+/// is rendered in a toast.
+fn validate_external_url(raw: &str) -> Result<String, String> {
+    // Rust's `trim` strips slightly more than JavaScript's (NEL, U+0085, for
+    // one), so a string the frontend would have rejected can reach the parser
+    // here with its edges shaved. That only ever removes outer whitespace —
+    // everything that survives still has to pass every check below — so the
+    // divergence cannot widen what gets opened.
+    let candidate = raw.trim();
+
+    if candidate.is_empty() {
+        return Err("Refused to open an empty URL.".to_string());
+    }
+    if candidate.len() > MAX_URL_LEN {
+        return Err(format!(
+            "Refused to open a URL longer than {MAX_URL_LEN} characters."
+        ));
+    }
+    if has_forbidden_char(candidate) {
+        return Err(
+            "Refused to open a URL containing whitespace, quotes or control characters."
+                .to_string(),
+        );
+    }
+
+    let parsed = Url::parse(candidate).map_err(|_| "Refused to open a malformed URL.".to_string())?;
+
+    // Scheme allowlist. Nothing else, ever — `file:`, `javascript:`, `data:`
+    // and every registered protocol handler stay out of reach of the
+    // container. The scheme is safe to interpolate: the parser restricts it to
+    // ASCII alphanumerics, `+`, `-` and `.`.
+    if parsed.scheme() != "http" && parsed.scheme() != "https" {
+        return Err(format!(
+            "Refused to open a {}: URL — only http and https are allowed.",
+            parsed.scheme()
+        ));
+    }
+    if parsed.host_str().is_none_or(str::is_empty) {
+        return Err("Refused to open a URL with no host.".to_string());
+    }
+    // `https://claude.ai@evil.tld/x` reads as claude.ai anywhere the string is
+    // truncated, and navigates to evil.tld.
+    if !parsed.username().is_empty() || parsed.password().is_some() {
+        return Err("Refused to open a URL containing embedded credentials.".to_string());
+    }
+
+    let normalized = parsed.to_string();
+    if normalized.len() > MAX_URL_LEN {
+        return Err(format!(
+            "Refused to open a URL longer than {MAX_URL_LEN} characters."
+        ));
+    }
+    // A normalized http(s) URL is ASCII by construction — the host is
+    // punycoded and everything after it is percent-encoded. Asserting it means
+    // nothing non-ASCII can reach an `execvp` argument, whatever the parser
+    // decides to do in a future version.
+    if !normalized.is_ascii() {
+        return Err("Refused to open a URL with non-ASCII characters.".to_string());
+    }
+
+    Ok(normalized)
+}
+
+/// Openers to try, in order, each as (program, leading arguments).
+///
+/// `xdg-open` first because it is what the desktop expects to be asked and
+/// honours the user's `mimeapps.list`. `gio open` second: it is present
+/// wherever glib is (which, for a GTK app's host, is everywhere) and resolves
+/// the handler through GIO rather than `xdg-open`'s shell heuristics, so it
+/// still works when the `x-scheme-handler/https` association `xdg-open` looks
+/// for is missing or points at something broken.
+#[cfg(target_os = "linux")]
+const OPENERS: &[(&str, &[&str])] = &[("xdg-open", &[]), ("gio", &["open"])];
+
+/// How long a candidate opener is given to fail before it is assumed to have
+/// worked.
+///
+/// `xdg-open` usually returns immediately (it hands the URL to a running
+/// browser and exits), but in its generic fallback mode it *is* the browser's
+/// parent and stays alive for the session. So "still running" cannot be read
+/// as failure, and "exited non-zero quickly" is the only negative signal there
+/// is — though not, on its own, a trustworthy one. See
+/// [`exit_code_means_nothing_was_launched`].
+#[cfg(target_os = "linux")]
+const OPENER_GRACE: std::time::Duration = std::time::Duration::from_millis(400);
+
+/// Whether a non-zero exit says the opener certainly launched nothing, and so
+/// that the next candidate can be tried without risking a second tab.
+///
+/// The loop used to treat every quick non-zero exit as "it did nothing" and
+/// fall through. That is safe for most of `xdg-open`'s documented codes — 1
+/// (syntax), 2 (file not found) and 3 (a required tool could not be found) are
+/// all statements that it never got as far as launching a handler, and 3 is the
+/// missing-association case `gio open` is in [`OPENERS`] for. 127 is the same
+/// statement made by a shell, which is how a `$BROWSER` or `x-www-browser`
+/// wrapper naming a program that does not exist comes back.
+///
+/// Code 4 is the one that cannot be read that way, and it is the catch-all:
+/// "the action failed" also covers a handler that *was* launched and then
+/// returned non-zero. A browser that takes the URL, opens the tab in an already
+/// running instance and exits non-zero for its own reasons ends up here, as
+/// does a wrapper script that does its job and then returns the exit status of
+/// something else. Falling through on that hands the same URL to a second
+/// opener: two tabs for one click, and for an OAuth link two authorize
+/// requests.
+///
+/// So anything not recognised below — 4, an unfamiliar code, or a death by
+/// signal (`code()` is `None`) — ends the loop rather than continuing it. The
+/// caller is told the opener failed, which is the honest report of an
+/// ambiguous outcome, and no second request is made on the user's behalf. Note
+/// what this costs: an opener that genuinely failed with code 4 no longer falls
+/// through to `gio`, so a user whose `xdg-open` fails that way sees an error
+/// where they previously might have got a tab.
+///
+/// This is reasoning from `xdg-open`'s documented exit codes, not from an
+/// observed double-open in this app.
+#[cfg(target_os = "linux")]
+fn exit_code_means_nothing_was_launched(code: Option<i32>) -> bool {
+    matches!(code, Some(1 | 2 | 3 | 127))
+}
+
+/// Spawn `url` with an opener, under a sanitized environment.
+#[cfg(target_os = "linux")]
+fn spawn_with_clean_env(url: &str) -> Result<(), String> {
+    let current: BTreeMap<String, String> = std::env::vars().collect();
+    let pristine = PRISTINE_ENV.get().cloned().unwrap_or_else(|| current.clone());
+    let appdir = current.get("APPDIR").cloned();
+    let changes = sanitize_child_env(&current, &pristine, appdir.as_deref());
+
+    let mut failures: Vec<String> = Vec::new();
+
+    for (program, leading) in OPENERS {
+        let mut command = std::process::Command::new(program);
+        command.args(*leading).arg(url);
+        // The bundle's own identity is not the child's business either, and a
+        // browser that re-execs itself through a wrapper script can pick these
+        // up.
+        for var in ["APPDIR", "APPIMAGE", "ARGV0", "OWD"] {
+            command.env_remove(var);
+        }
+        for (key, value) in &changes {
+            match value {
+                Some(value) => command.env(key, value),
+                None => command.env_remove(key),
+            };
+        }
+        // Detached: the opener must not inherit our stdio, or a browser
+        // writing to stderr keeps a pipe to us open for the session.
+        command
+            .stdin(std::process::Stdio::null())
+            .stdout(std::process::Stdio::null())
+            .stderr(std::process::Stdio::null());
+
+        // A spawn failure — `ErrorKind::NotFound` for an opener that is not
+        // installed, `PermissionDenied` for one that cannot be executed — is
+        // the unambiguous case: nothing ran, so nothing was opened, and the
+        // next candidate is free to try.
+        let mut child = match command.spawn() {
+            Ok(child) => child,
+            Err(err) => {
+                failures.push(format!("{program}: {err}"));
+                continue;
+            }
+        };
+
+        std::thread::sleep(OPENER_GRACE);
+        match child.try_wait() {
+            Ok(Some(status)) if !status.success() => {
+                failures.push(format!("{program} exited with {status}"));
+                // A program that *ran* is not a program that did nothing.
+                if !exit_code_means_nothing_was_launched(status.code()) {
+                    return Err(format!(
+                        "Could not confirm the link opened. Tried: {}. It may have opened anyway \
+                         — check your browser before trying again.",
+                        failures.join("; ")
+                    ));
+                }
+                continue;
+            }
+            Ok(_) => {}
+            Err(err) => {
+                failures.push(format!("{program}: could not be waited on: {err}"));
+                continue;
+            }
+        }
+
+        // Still running (it is the browser's parent) — reap it off-thread so it
+        // does not become a zombie for the life of the app.
+        std::thread::spawn(move || {
+            let _ = child.wait();
+        });
+        return Ok(());
+    }
+
+    Err(format!(
+        "Could not open the link. Tried: {}. Check that xdg-utils is installed and that a default browser is set.",
+        failures.join("; ")
+    ))
+}
+
+/// Open `url` in the user's browser.
+///
+/// On Linux this goes through [`spawn_with_clean_env`] rather than
+/// `@tauri-apps/plugin-opener`, for the AppImage reasons in this module's
+/// documentation (triple-c#34). macOS and Windows keep the plugin's path —
+/// neither has the environment problem, and `open`/`ShellExecute` are the
+/// right calls there — but they are reached through this same command so the
+/// frontend has one call site with one set of validation rules.
+///
+/// Errors are returned rather than logged-and-swallowed: "Open" silently doing
+/// nothing is the bug being fixed, so the failure has to be something the UI
+/// can show.
+#[tauri::command]
+pub async fn open_url_external(app: tauri::AppHandle, url: String) -> Result<(), String> {
+    let validated = validate_external_url(&url)?;
+
+    #[cfg(target_os = "linux")]
+    {
+        let _ = &app;
+        tauri::async_runtime::spawn_blocking(move || spawn_with_clean_env(&validated))
+            .await
+            .map_err(|err| format!("Could not open the link: {err}"))?
+    }
+
+    #[cfg(not(target_os = "linux"))]
+    {
+        use tauri_plugin_opener::OpenerExt;
+        app.opener()
+            .open_url(validated, None::<&str>)
+            .map_err(|err| format!("Could not open the link: {err}"))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn map(pairs: &[(&str, &str)]) -> BTreeMap<String, String> {
+        pairs
+            .iter()
+            .map(|(k, v)| (k.to_string(), v.to_string()))
+            .collect()
+    }
+
+    // ── URL re-validation ────────────────────────────────────────────────
+
+    #[test]
+    fn plain_http_and_https_urls_are_accepted() {
+        for url in [
+            "https://claude.ai/",
+            "http://localhost:1420/callback?code=abc",
+            "https://example.com/path#frag",
+        ] {
+            assert!(validate_external_url(url).is_ok(), "{url} should be allowed");
+        }
+    }
+
+    #[test]
+    fn urls_are_returned_normalized() {
+        assert_eq!(
+            validate_external_url("https://Example.COM").unwrap(),
+            "https://example.com/"
+        );
+    }
+
+    #[test]
+    fn only_http_and_https_survive() {
+        for url in [
+            "file:///etc/passwd",
+            "javascript:alert(1)",
+            "data:text/html,<script>",
+            "ftp://example.com/x",
+            "vscode://foo/bar",
+            "mailto:someone@example.com",
+        ] {
+            assert!(
+                validate_external_url(url).is_err(),
+                "{url} must not be openable"
+            );
+        }
+    }
+
+    #[test]
+    fn embedded_credentials_are_refused() {
+        for url in [
+            "https://claude.ai@evil.tld/x",
+            "https://user:pass@example.com/",
+            "https://:pass@example.com/",
+        ] {
+            assert!(
+                validate_external_url(url).is_err(),
+                "{url} must not be openable"
+            );
+        }
+    }
+
+    #[test]
+    fn control_characters_and_whitespace_are_refused() {
+        // `\n` in particular: parsers that strip it would turn the first of
+        // these into a `javascript:` URL.
+        for url in [
+            "java\nscript:alert(1)",
+            "https://example.com/\u{7f}",
+            "https://example.com/\u{85}x",
+            "https://example.com/a b",
+            "https://example.com/\u{00a0}x",
+            "https://example.com/\"",
+            "https://example.com/'",
+            "https://example.com/`",
+        ] {
+            assert!(
+                validate_external_url(url).is_err(),
+                "{url:?} must not be openable"
+            );
+        }
+    }
+
+    #[test]
+    fn empty_and_oversized_are_refused() {
+        assert!(validate_external_url("").is_err());
+        assert!(validate_external_url("   ").is_err());
+        let long = format!("https://example.com/{}", "a".repeat(MAX_URL_LEN));
+        assert!(validate_external_url(&long).is_err());
+    }
+
+    #[test]
+    fn a_host_is_required() {
+        assert!(validate_external_url("https://").is_err());
+        assert!(validate_external_url("http://:8080/").is_err());
+        // Not a missing host: WHATWG's "special authority ignore slashes"
+        // state eats the third slash, so this is the host `path` in both
+        // `new URL()` and here. Asserted so the parity is on the record.
+        assert_eq!(
+            validate_external_url("http:///path").unwrap(),
+            "http://path/"
+        );
+    }
+
+    #[test]
+    fn error_messages_never_echo_the_input() {
+        // The input is attacker-controlled and the message goes into a toast.
+        let err = validate_external_url("file:///home/someone/.ssh/id_rsa").unwrap_err();
+        assert!(!err.contains("id_rsa"), "message leaked the input: {err}");
+    }
+
+    // ── Environment sanitization ─────────────────────────────────────────
+
+    #[test]
+    fn appdir_entries_are_stripped_and_the_users_own_are_kept() {
+        let current = map(&[
+            ("APPDIR", "/tmp/.mount_abc"),
+            ("LD_LIBRARY_PATH", "/tmp/.mount_abc/usr/lib:/opt/mine/lib"),
+            ("XDG_DATA_DIRS", "/tmp/.mount_abc/usr/share:/usr/share"),
+        ]);
+        let changes = sanitize_child_env(&current, &current, Some("/tmp/.mount_abc"));
+        assert_eq!(
+            changes,
+            vec![
+                (
+                    "LD_LIBRARY_PATH".to_string(),
+                    Some("/opt/mine/lib".to_string())
+                ),
+                ("XDG_DATA_DIRS".to_string(), Some("/usr/share".to_string())),
+            ]
+        );
+    }
+
+    #[test]
+    fn a_variable_that_is_entirely_appdir_is_removed() {
+        let current = map(&[
+            ("APPDIR", "/tmp/.mount_abc"),
+            ("GTK_PATH", "/tmp/.mount_abc/usr/lib/gtk-3.0"),
+            (
+                "GDK_PIXBUF_MODULE_FILE",
+                "/tmp/.mount_abc/usr/lib/gdk-pixbuf/loaders.cache",
+            ),
+        ]);
+        let changes = sanitize_child_env(&current, &current, Some("/tmp/.mount_abc"));
+        assert_eq!(
+            changes,
+            vec![
+                ("GDK_PIXBUF_MODULE_FILE".to_string(), None),
+                ("GTK_PATH".to_string(), None),
+            ]
+        );
+    }
+
+    #[test]
+    fn a_saved_original_is_restored_rather_than_unset() {
+        // Restoring beats unsetting: the user may have had one of their own.
+        for saved_as in ["LD_LIBRARY_PATH_ORIG", "APPIMAGE_ORIGINAL_LD_LIBRARY_PATH"] {
+            let current = map(&[
+                ("APPDIR", "/tmp/.mount_abc"),
+                ("LD_LIBRARY_PATH", "/tmp/.mount_abc/usr/lib"),
+                (saved_as, "/home/someone/lib"),
+            ]);
+            let changes = sanitize_child_env(&current, &current, Some("/tmp/.mount_abc"));
+            assert_eq!(
+                changes,
+                vec![(
+                    "LD_LIBRARY_PATH".to_string(),
+                    Some("/home/someone/lib".to_string())
+                )],
+                "{saved_as} should be restored"
+            );
+        }
+    }
+
+    #[test]
+    fn an_empty_saved_original_means_it_was_unset() {
+        let current = map(&[
+            ("APPDIR", "/tmp/.mount_abc"),
+            ("LD_LIBRARY_PATH", "/tmp/.mount_abc/usr/lib"),
+            ("LD_LIBRARY_PATH_ORIG", ""),
+        ]);
+        let changes = sanitize_child_env(&current, &current, Some("/tmp/.mount_abc"));
+        assert_eq!(changes, vec![("LD_LIBRARY_PATH".to_string(), None)]);
+    }
+
+    #[test]
+    fn our_own_set_var_is_undone_from_the_pristine_snapshot() {
+        // The leak `main.rs` documents: we set this after start-up, so the
+        // start-up snapshot is what says it should not exist at all.
+        let pristine = map(&[("HOME", "/home/someone")]);
+        let current = map(&[
+            ("HOME", "/home/someone"),
+            ("WEBKIT_DISABLE_DMABUF_RENDERER", "1"),
+        ]);
+        let changes = sanitize_child_env(&current, &pristine, None);
+        assert_eq!(
+            changes,
+            vec![("WEBKIT_DISABLE_DMABUF_RENDERER".to_string(), None)]
+        );
+    }
+
+    #[test]
+    fn a_value_the_user_set_themselves_is_left_alone() {
+        let pristine = map(&[("WEBKIT_DISABLE_DMABUF_RENDERER", "1")]);
+        let current = pristine.clone();
+        assert!(sanitize_child_env(&current, &pristine, None).is_empty());
+    }
+
+    #[test]
+    fn outside_an_appimage_nothing_is_touched() {
+        let env = map(&[
+            ("PATH", "/usr/bin:/bin"),
+            ("LD_LIBRARY_PATH", "/opt/mine/lib"),
+            ("XDG_DATA_DIRS", "/usr/share"),
+        ]);
+        assert!(
+            sanitize_child_env(&env, &env, None).is_empty(),
+            "a dev build or distro build must not have its environment rewritten"
+        );
+    }
+
+    #[test]
+    fn nothing_is_invented_for_variables_that_were_never_set() {
+        let env = map(&[("APPDIR", "/tmp/.mount_abc")]);
+        assert!(sanitize_child_env(&env, &env, Some("/tmp/.mount_abc")).is_empty());
+    }
+
+    #[test]
+    fn a_prefix_that_merely_looks_like_appdir_is_not_stripped() {
+        // `/tmp/.mount_abc-other` is not inside `/tmp/.mount_abc`.
+        let env = map(&[
+            ("APPDIR", "/tmp/.mount_abc"),
+            ("LD_LIBRARY_PATH", "/tmp/.mount_abc-other/lib"),
+        ]);
+        assert!(sanitize_child_env(&env, &env, Some("/tmp/.mount_abc")).is_empty());
+    }
+
+    #[test]
+    fn a_trailing_slash_on_appdir_still_matches() {
+        let env = map(&[
+            ("APPDIR", "/tmp/.mount_abc/"),
+            ("GTK_PATH", "/tmp/.mount_abc/usr/lib/gtk-3.0"),
+        ]);
+        let changes = sanitize_child_env(&env, &env, Some("/tmp/.mount_abc/"));
+        assert_eq!(changes, vec![("GTK_PATH".to_string(), None)]);
+    }
+}
+
+#[cfg(all(test, target_os = "linux"))]
+mod opener_fallback_tests {
+    use super::*;
+
+    /// The codes `xdg-open` documents as "nothing was launched". Falling
+    /// through to the next opener on these is what keeps `gio open` reachable
+    /// for the case it was added for: no usable `x-scheme-handler/https`
+    /// association.
+    #[test]
+    fn the_codes_that_mean_no_handler_ran_fall_through() {
+        for code in [1, 2, 3, 127] {
+            assert!(
+                exit_code_means_nothing_was_launched(Some(code)),
+                "exit {code} means the opener never launched anything"
+            );
+        }
+    }
+
+    /// The regression this guards: `xdg-open` returns 4 both when it could not
+    /// act and when the handler it launched returned non-zero — including a
+    /// browser that had already opened the tab. Trying `gio open` next would
+    /// open it a second time, which for an OAuth URL is a second authorize
+    /// request.
+    #[test]
+    fn an_exit_that_may_follow_a_successful_open_does_not_fall_through() {
+        assert!(!exit_code_means_nothing_was_launched(Some(4)));
+        for code in [5, 7, 126, 255] {
+            assert!(
+                !exit_code_means_nothing_was_launched(Some(code)),
+                "exit {code} is not a documented 'did nothing', so it must not be assumed to be one"
+            );
+        }
+    }
+
+    /// Killed by a signal: `code()` is `None` and the outcome is unknowable,
+    /// so it is treated like any other unrecognised exit.
+    #[test]
+    fn a_death_by_signal_does_not_fall_through() {
+        assert!(!exit_code_means_nothing_was_launched(None));
+    }
+}

app/src-tauri/src/web_terminal/terminal.html

@@ -431,6 +431,18 @@
   const mobileInput = document.getElementById('mobileInput');
   const btnEnter = document.getElementById('btnEnter');
   const btnNewline = document.getElementById('btnNewline');
+
+  // Whether the *active* session understands ESC+CR as "insert a newline".
+  //
+  // Only Claude Code does. `bash -l` has no readline binding for `\e\r`, so
+  // sending it there is a silent no-op — which is worse from the mobile bar
+  // than from a hardware key, because the bar puts a dedicated button on
+  // screen that appears to do nothing. The xterm key handler is already scoped
+  // this way; these two paths were not.
+  function activeSessionTakesEscCr() {
+    const s = activeSessionId && sessions[activeSessionId];
+    return !!s && s.type === 'claude';
+  }
   const btnTab = document.getElementById('btnTab');
   const btnCtrlC = document.getElementById('btnCtrlC');
   const scrollBottomBtn = document.getElementById('scrollBottomBtn');
@@ -590,7 +602,7 @@
         updateProjectList(msg.projects);
         break;
       case 'opened':
-        onSessionOpened(msg.session_id, msg.project_name);
+        onSessionOpened(msg.session_id, msg.project_name, msg.session_type);
         break;
       case 'output':
         onSessionOutput(msg.session_id, msg.data);
@@ -641,8 +653,18 @@
     });
   }
 
-  function onSessionOpened(sessionId, projectName) {
-    const sessionType = pendingSessionType || 'claude';
+  function onSessionOpened(sessionId, projectName, serverSessionType) {
+    // Prefer the type the *server* reports for this session. The old path read
+    // a single `pendingSessionType` global set at request time, so opening two
+    // sessions before the first reply landed swapped their labels — routine on
+    // mobile, where nothing disables the buttons. That was cosmetic until
+    // Shift+Enter became type-dependent: a Claude session labelled `shell`
+    // sends a bare CR and submits a half-written prompt.
+    //
+    // The fallback keeps an older server working, and defaults to `claude`,
+    // which is the safe direction — ESC+CR is an unbound no-op in bash, while
+    // a bare CR in Claude Code loses the prompt.
+    const sessionType = serverSessionType || pendingSessionType || 'claude';
     pendingSessionType = null;
 
     // Create terminal
@@ -735,7 +757,13 @@
         sessionType === 'claude'
       ) {
         sendTerminalInput('\x1b\r');
-        return false; // xterm must not also send a bare CR, which submits
+        // `preventDefault()` is what stops the submit, not the `return false`.
+        // xterm's `_keyDown` returns before setting `_keyDownHandled`, so
+        // `_keyPress` still fires and emits a bare CR for Enter — inserting the
+        // newline and then submitting the prompt anyway. See the same comment
+        // in TerminalView.tsx.
+        e.preventDefault();
+        return false;
       }
       return true;
     });
@@ -791,6 +819,7 @@
       switchToSession(remaining[remaining.length - 1]);
     } else {
       activeSessionId = null;
+      syncNewlineButton();
       emptyState.style.display = '';
     }
   }
@@ -817,6 +846,7 @@
 
   function switchToSession(sessionId) {
     activeSessionId = sessionId;
+    syncNewlineButton();
 
     // Update tab styles
     document.querySelectorAll('.tab').forEach(t => t.classList.remove('active'));
@@ -896,7 +926,7 @@
       // reasoning, as the terminal's own key handler above. A hardware
       // keyboard on a tablet is the only way to reach this; the phone case is
       // the dedicated newline button beside Enter.
-      sendTerminalInput(e.shiftKey ? '\x1b\r' : '\r');
+      sendTerminalInput(e.shiftKey && activeSessionTakesEscCr() ? '\x1b\r' : '\r');
     } else if (e.key === 'Tab') {
       e.preventDefault();
       sendTerminalInput('\t');
@@ -904,7 +934,27 @@
   });
 
   btnEnter.onclick = () => { sendTerminalInput('\r'); mobileInput.focus(); };
-  btnNewline.onclick = () => { sendTerminalInput('\x1b\r'); mobileInput.focus(); };
+  btnNewline.onclick = () => {
+    if (!activeSessionTakesEscCr()) { mobileInput.focus(); return; }
+    sendTerminalInput('\x1b\r');
+    mobileInput.focus();
+  };
+
+  // Keep the button's affordance honest: on a shell tab there is no byte that
+  // means "newline without running the line", so the control is disabled
+  // rather than left looking live.
+  function syncNewlineButton() {
+    const usable = activeSessionTakesEscCr();
+    btnNewline.disabled = !usable;
+    btnNewline.title = usable
+      ? 'Insert a newline without submitting (Shift+Enter)'
+      : 'Only Claude sessions support this — a shell runs the line instead';
+  }
+
+  // With no session open yet, `activeSessionTakesEscCr()` is already false —
+  // but nothing had called this, so the button rendered live before the first
+  // tab existed.
+  syncNewlineButton();
   btnTab.onclick = () => { sendTerminalInput('\t'); mobileInput.focus(); };
   btnCtrlC.onclick = () => { sendTerminalInput('\x03'); mobileInput.focus(); };
 

app/src-tauri/src/web_terminal/ws_handler.rs

@@ -46,6 +46,16 @@ enum ServerMessage {
     Opened {
         session_id: String,
         project_name: String,
+        /// Echoed back so the client can label the session from the reply
+        /// rather than from a global set at request time.
+        ///
+        /// Without it the client correlates through a single
+        /// `pendingSessionType`, so opening two sessions before the first
+        /// reply lands swaps their labels. That used to be cosmetic; it stopped
+        /// being cosmetic when Shift+Enter became type-dependent, because a
+        /// Claude session mislabelled as a shell now submits a half-written
+        /// prompt instead of inserting a newline.
+        session_type: String,
     },
     Output {
         session_id: String,
@@ -196,6 +206,11 @@ pub async fn handle_connection(socket: WebSocket, state: Arc<WebTerminalState>)
     writer_handle.abort();
 }
 
+/// The desktop terminal's update prelude, reused verbatim. Shared rather than
+/// copied so the web terminal cannot drift from it — a duplicated `const` with
+/// a "keep these identical" comment is only as good as the next reader.
+use crate::commands::terminal_commands::UPDATE_PRELUDE;
+
 /// Build the command for a terminal session, mirroring terminal_commands.rs logic.
 fn build_terminal_cmd(project: &Project, settings_store: &crate::storage::settings_store::SettingsStore) -> Vec<String> {
     let is_bedrock_profile = project.backend == Backend::Bedrock
@@ -207,17 +222,6 @@ fn build_terminal_cmd(project: &Project, settings_store: &crate::storage::settin
 
     let permission_args = project.effective_permission_mode().cli_args();
 
-    if !is_bedrock_profile {
-        let mut cmd = vec!["claude".to_string()];
-        cmd.extend(permission_args);
-        return cmd;
-    }
-
-    let profile = aws_commands::resolve_profile_for_project(
-        project,
-        settings_store.get().global_aws.aws_profile.as_deref(),
-    );
-
     // The args are interpolated into a shell script string below, so
     // single-quote each one.
     let permission_flags: String = permission_args
@@ -226,6 +230,19 @@ fn build_terminal_cmd(project: &Project, settings_store: &crate::storage::settin
         .collect();
     let claude_cmd = format!("exec claude{}", permission_flags);
 
+    if !is_bedrock_profile {
+        return vec![
+            "bash".to_string(),
+            "-c".to_string(),
+            format!("{}\n{}\n", UPDATE_PRELUDE, claude_cmd),
+        ];
+    }
+
+    let profile = aws_commands::resolve_profile_for_project(
+        project,
+        settings_store.get().global_aws.aws_profile.as_deref(),
+    );
+
     let script = format!(
         r#"
 echo "Validating AWS session for profile '{profile}'..."
@@ -250,9 +267,11 @@ else
         echo ""
     fi
 fi
+{update_prelude}
 {claude_cmd}
 "#,
         profile = profile,
+        update_prelude = UPDATE_PRELUDE,
         claude_cmd = claude_cmd
     );
 
@@ -319,6 +338,11 @@ async fn handle_open(
     let _ = out_tx.send(ServerMessage::Opened {
         session_id,
         project_name,
+        // Derived from the same match that chose `cmd` above, not echoed from
+        // the request: anything that is not exactly "bash" runs Claude, so
+        // echoing the raw value would label an unrecognised string as its own
+        // type and put the client back where it started.
+        session_type: if session_type == Some("bash") { "bash" } else { "claude" }.to_string(),
     });
 
     Ok(())

app/src/App.tsx

@@ -4,6 +4,7 @@ import { listen } from "@tauri-apps/api/event";
 import Sidebar from "./components/layout/Sidebar";
 import TopBar from "./components/layout/TopBar";
 import StatusBar from "./components/layout/StatusBar";
+import NotesDock from "./components/layout/NotesDock";
 import TerminalView from "./components/terminal/TerminalView";
 import DockerInstallDialog from "./components/DockerInstallDialog";
 import ProjectHome from "./components/projects/home/ProjectHome";
@@ -161,6 +162,7 @@ export default function App() {
             </div>
           )}
         </main>
+        <NotesDock />
       </div>
       <StatusBar stt={stt} />
       <ToastHost />

app/src/components/DockerInstallDialog.tsx

@@ -1,6 +1,6 @@
 import { useEffect, useState } from "react";
-import { openUrl } from "@tauri-apps/plugin-opener";
 import { useInstallHelper } from "../hooks/useInstallHelper";
+import { openUrlExternal } from "../lib/tauri-commands";
 import { useDocker } from "../hooks/useDocker";
 import Modal from "./ui/Modal";
 import Button from "./ui/Button";
@@ -41,7 +41,7 @@ export default function DockerInstallDialog({ onClose }: Props) {
   const handleOpenDocs = async () => {
     if (!options) return;
     try {
-      await openUrl(options.docs_url);
+      await openUrlExternal(options.docs_url);
     } catch (e) {
       console.error("Failed to open docs URL:", e);
     }

app/src/components/layout/MainTabs.tsx

@@ -10,6 +10,7 @@ import {
 } from "../../store/appState";
 import { effectivePermissionMode } from "../projects/PermissionModeControl";
 import { ProjectStatusIndicator } from "../ui/StatusIndicator";
+import { sessionDisplayName } from "../../lib/sessionName";
 import type { PermissionMode } from "../../lib/types";
 
 interface ContextMenuState {
@@ -195,11 +196,10 @@ export default function MainTabs() {
     }
     const session = sessions.find((s) => s.id === tabKeyId(key));
     if (!session) return "";
-    const custom = getCustomName(session.projectId, session.id);
-    return custom
-      ? `${session.projectName}: ${custom}`
-      : (session.sessionName ?? session.projectName) +
-          (session.sessionType === "bash" ? " (bash)" : "");
+    return sessionDisplayName(
+      session,
+      projects.find((p) => p.id === session.projectId),
+    );
   };
 
   const endDrag = () => {
@@ -358,13 +358,7 @@ export default function MainTabs() {
     const session = sessions.find((s) => s.id === sessionId);
     if (!session) return null;
     const project = projects.find((p) => p.id === session.projectId);
-    const customName = getCustomName(session.projectId, session.id);
-    const baseLabel =
-      (session.sessionName ?? session.projectName) +
-      (session.sessionType === "bash" ? " (bash)" : "");
-    const displayLabel = customName
-      ? `${session.projectName}: ${customName}`
-      : baseLabel;
+    const displayLabel = sessionDisplayName(session, project);
     const isRenaming = renamingId === session.id;
     const badge = project ? MODE_BADGE[effectivePermissionMode(project)] : null;
 

app/src/components/layout/NotesDock.test.tsx

@@ -0,0 +1,113 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { render, screen, fireEvent } from "@testing-library/react";
+import NotesDock from "./NotesDock";
+import type { Project, TerminalSession } from "../../lib/types";
+
+vi.mock("../notes/NotesDockPanel", () => ({
+  default: ({ projectId }: { projectId: string }) => (
+    <div data-testid="panel">{`panel:${projectId}`}</div>
+  ),
+}));
+
+let state: Record<string, unknown> = {};
+vi.mock("../../store/appState", () => ({
+  useAppState: Object.assign(
+    (selector: (s: unknown) => unknown) => selector(state),
+    { getState: () => state },
+  ),
+  isHomeTab: (k: string) => k.startsWith("home:"),
+  isTerminalTab: (k: string) => k.startsWith("term:"),
+  tabKeyId: (k: string) => k.slice(k.indexOf(":") + 1),
+  // The mocked store module still needs to supply the width constants the
+  // dock imports from it for the separator's aria-value attributes.
+  NOTES_DOCK_MIN_WIDTH: 260,
+  NOTES_DOCK_MAX_WIDTH: 720,
+}));
+
+const session: TerminalSession = {
+  id: "s1",
+  projectId: "p9",
+  projectName: "api",
+  sessionType: "claude",
+  sessionName: null,
+};
+
+beforeEach(() => {
+  state = {
+    notesDockOpen: true,
+    setNotesDockOpen: vi.fn(),
+    toggleNotesDock: vi.fn(),
+    notesDockWidth: 352,
+    setNotesDockWidth: vi.fn(),
+    activeTabKey: null,
+    sessions: [session],
+    projects: [{ id: "p9", name: "api" } as unknown as Project],
+  };
+});
+
+describe("NotesDock", () => {
+  it("renders nothing when closed", () => {
+    state.notesDockOpen = false;
+    const { container } = render(<NotesDock />);
+    expect(container).toBeEmptyDOMElement();
+  });
+
+  it("follows a project home tab", () => {
+    state.activeTabKey = "home:p1";
+    render(<NotesDock />);
+    expect(screen.getByTestId("panel")).toHaveTextContent("panel:p1");
+  });
+
+  it("follows the project of the active terminal tab", () => {
+    // The dock exists to be visible while the agent runs, so a terminal tab
+    // must resolve to its project, not to nothing.
+    state.activeTabKey = "term:s1";
+    render(<NotesDock />);
+    expect(screen.getByTestId("panel")).toHaveTextContent("panel:p9");
+  });
+
+  it("explains itself when no project is active", () => {
+    state.activeTabKey = null;
+    render(<NotesDock />);
+    expect(screen.queryByTestId("panel")).not.toBeInTheDocument();
+    expect(screen.getByText(/open a project/i)).toBeInTheDocument();
+  });
+
+  it("shows nothing for a terminal whose session has gone", () => {
+    state.activeTabKey = "term:vanished";
+    render(<NotesDock />);
+    expect(screen.queryByTestId("panel")).not.toBeInTheDocument();
+  });
+
+  it("renders at the stored width", () => {
+    state.activeTabKey = "home:p1";
+    state.notesDockWidth = 420;
+    render(<NotesDock />);
+    expect(screen.getByLabelText("Notes")).toHaveStyle({ width: "420px" });
+  });
+
+  it("has a keyboard-reachable resize handle", () => {
+    // Drag is a mouse gesture; a separator that only responds to pointer
+    // events is unusable without one.
+    state.activeTabKey = "home:p1";
+    render(<NotesDock />);
+    const handle = screen.getByRole("separator", { name: /resize notes/i });
+    fireEvent.keyDown(handle, { key: "ArrowLeft" });
+    expect(state.setNotesDockWidth).toHaveBeenCalled();
+  });
+
+  it("widens on ArrowLeft and narrows on ArrowRight, by the exact step", () => {
+    // The dock sits on the right edge, so dragging or pressing left grows it
+    // and right shrinks it. Asserting only "was called" would pass even if
+    // the branches were swapped or the sign inverted.
+    state.activeTabKey = "home:p1";
+    render(<NotesDock />);
+    const handle = screen.getByRole("separator", { name: /resize notes/i });
+
+    fireEvent.keyDown(handle, { key: "ArrowLeft" });
+    expect(state.setNotesDockWidth).toHaveBeenLastCalledWith(368);
+
+    fireEvent.keyDown(handle, { key: "ArrowRight" });
+    expect(state.setNotesDockWidth).toHaveBeenLastCalledWith(336);
+  });
+});

app/src/components/layout/NotesDock.tsx

@@ -0,0 +1,128 @@
+import { useShallow } from "zustand/react/shallow";
+import {
+  useAppState,
+  isHomeTab,
+  isTerminalTab,
+  tabKeyId,
+  NOTES_DOCK_MIN_WIDTH,
+  NOTES_DOCK_MAX_WIDTH,
+} from "../../store/appState";
+import NotesDockPanel from "../notes/NotesDockPanel";
+import Button from "../ui/Button";
+
+/**
+ * Notes beside whatever is on screen.
+ *
+ * Project Home and Terminal are sibling top-level tabs, so notes living only
+ * in a sub-tab would be hidden exactly when the agent is running — which is
+ * when a note is worth sending. The dock is the answer to that.
+ *
+ * **It takes space from inside the window and never resizes it.** Growing the
+ * OS window was tried and rejected on evidence: honoured under XWayland,
+ * silently corrupting under native Wayland, where `outer_position()` returns a
+ * confident `Ok(0,0)` for a window that is somewhere else. See the design doc,
+ * §6.1. Narrowing the terminal instead costs nothing — `TerminalView`'s
+ * ResizeObserver already reflows xterm and resizes the container PTY.
+ */
+export default function NotesDock() {
+  const {
+    notesDockOpen,
+    setNotesDockOpen,
+    notesDockWidth,
+    setNotesDockWidth,
+    activeTabKey,
+    sessions,
+  } = useAppState(
+    useShallow((s) => ({
+      notesDockOpen: s.notesDockOpen,
+      setNotesDockOpen: s.setNotesDockOpen,
+      notesDockWidth: s.notesDockWidth,
+      setNotesDockWidth: s.setNotesDockWidth,
+      activeTabKey: s.activeTabKey,
+      sessions: s.sessions,
+    })),
+  );
+
+  // Dragging the separator. Pointer capture rather than window listeners, so
+  // the drag survives the pointer crossing the terminal — which swallows
+  // events — and ends correctly if the button is released outside the window.
+  const onPointerDown = (e: React.PointerEvent<HTMLDivElement>) => {
+    e.preventDefault();
+    const handle = e.currentTarget;
+    handle.setPointerCapture(e.pointerId);
+    const startX = e.clientX;
+    const startWidth = notesDockWidth;
+    // The dock is on the right, so dragging left widens it.
+    const onMove = (move: PointerEvent) =>
+      setNotesDockWidth(startWidth + (startX - move.clientX));
+    const onUp = () => {
+      handle.releasePointerCapture(e.pointerId);
+      handle.removeEventListener("pointermove", onMove);
+      handle.removeEventListener("pointerup", onUp);
+    };
+    handle.addEventListener("pointermove", onMove);
+    handle.addEventListener("pointerup", onUp);
+  };
+
+  const onHandleKeyDown = (e: React.KeyboardEvent<HTMLDivElement>) => {
+    const step = e.shiftKey ? 64 : 16;
+    if (e.key === "ArrowLeft") {
+      e.preventDefault();
+      setNotesDockWidth(notesDockWidth + step);
+    } else if (e.key === "ArrowRight") {
+      e.preventDefault();
+      setNotesDockWidth(notesDockWidth - step);
+    }
+  };
+
+  if (!notesDockOpen) return null;
+
+  // Follow whatever is in front: a home tab is its own project, a terminal tab
+  // is the project it belongs to.
+  let projectId: string | null = null;
+  if (activeTabKey && isHomeTab(activeTabKey)) {
+    projectId = tabKeyId(activeTabKey);
+  } else if (activeTabKey && isTerminalTab(activeTabKey)) {
+    projectId =
+      sessions.find((s) => s.id === tabKeyId(activeTabKey))?.projectId ?? null;
+  }
+
+  return (
+    <aside
+      aria-label="Notes"
+      style={{ width: `${notesDockWidth}px` }}
+      className="relative flex-shrink-0 flex flex-col min-h-0 bg-[var(--bg-secondary)] border border-[var(--border-color)] rounded-[var(--radius-panel)] overflow-hidden"
+    >
+      {/* Separator, not decoration: it carries a role and arrow keys, because
+          a resize that only answers to a drag is unavailable to anyone not
+          using a mouse. */}
+      <div
+        role="separator"
+        aria-label="Resize notes panel"
+        aria-orientation="vertical"
+        aria-valuenow={notesDockWidth}
+        aria-valuemin={NOTES_DOCK_MIN_WIDTH}
+        aria-valuemax={NOTES_DOCK_MAX_WIDTH}
+        tabIndex={0}
+        onPointerDown={onPointerDown}
+        onKeyDown={onHandleKeyDown}
+        className="absolute left-0 top-0 h-full w-1.5 cursor-col-resize hover:bg-[var(--accent-muted)] transition-colors"
+      />
+      <div className="flex items-center justify-between gap-2 px-3 h-9 flex-shrink-0 border-b border-[var(--border-color)]">
+        <h2 className="text-[13px] font-semibold text-[var(--text-primary)]">Notes</h2>
+        <Button variant="ghost" onClick={() => setNotesDockOpen(false)} aria-label="Close notes">
+          Close
+        </Button>
+      </div>
+      <div className="flex-1 min-h-0">
+        {projectId ? (
+          <NotesDockPanel projectId={projectId} />
+        ) : (
+          <p className="p-4 text-[13px] text-[var(--text-secondary)]">
+            Open a project or a terminal to see its notes.
+          </p>
+        )}
+      </div>
+    </aside>
+  );
+}

app/src/components/layout/StatusBar.tsx

@@ -10,7 +10,7 @@ interface Props {
 export default function StatusBar({ stt }: Props) {
   const {
     projects, sessions, terminalHasSelection, activeSessionId, sttEnabled,
-    terminalAtBottom, scrollActiveToBottom,
+    notesDockOpen, toggleNotesDock, terminalMouseCaptured, releaseActiveMouse,
   } = useAppState(
     useShallow(s => ({
       projects: s.projects,
@@ -18,8 +18,10 @@ export default function StatusBar({ stt }: Props) {
       terminalHasSelection: s.terminalHasSelection,
       activeSessionId: s.activeSessionId,
       sttEnabled: s.appSettings?.stt?.enabled,
-      terminalAtBottom: s.terminalAtBottom,
-      scrollActiveToBottom: s.scrollActiveToBottom,
+      notesDockOpen: s.notesDockOpen,
+      toggleNotesDock: s.toggleNotesDock,
+      terminalMouseCaptured: s.terminalMouseCaptured,
+      releaseActiveMouse: s.releaseActiveMouse,
     }))
   );
   const running = projects.filter((p) => p.status === "running").length;
@@ -58,17 +60,26 @@ export default function StatusBar({ stt }: Props) {
           </span>
         </>
       )}
-      {/* Right-aligned controls: Jump to Current + STT mic */}
+      {/* Right-aligned controls: mouse release + Notes + STT mic */}
       <div className="ml-auto flex items-center gap-3 pl-2">
-        {activeSessionId && !terminalAtBottom && (
+        {activeSessionId && terminalMouseCaptured && (
           <button
-            onClick={() => scrollActiveToBottom()}
+            data-mouse-release="true"
+            onClick={() => releaseActiveMouse()}
             className="text-[var(--accent)] hover:text-[var(--accent-hover)] cursor-pointer"
-            title="Scroll the terminal to the latest output"
+            title="A program in the container is reading the mouse, so clicks and drags go to it instead of selecting text. Click, or press Ctrl+Shift+X, to take it back. To select text without taking it back, hold Shift while dragging (Option on macOS)."
           >
-            Jump to Current ↓
+            🖱 Mouse captured — release
           </button>
         )}
+        <button
+          onClick={toggleNotesDock}
+          aria-pressed={notesDockOpen}
+          className="text-[var(--accent)] hover:text-[var(--accent-hover)] cursor-pointer"
+          title="Show or hide the notes panel beside the current tab"
+        >
+          Notes
+        </button>
         {sttEnabled && activeSessionId && (
           <SttButton
             state={stt.state}

app/src/components/notes/NoteEditor.tsx

@@ -0,0 +1,71 @@
+import SendToAgentButton from "./SendToAgentButton";
+import Button from "../ui/Button";
+
+interface Props {
+  projectId: string;
+  title: string;
+  body: string;
+  onTitleChange: (value: string) => void;
+  onBodyChange: (value: string) => void;
+  onCommit: () => void;
+  onDelete: () => void;
+}
+
+/**
+ * Title and body, saved when a field loses focus.
+ *
+ * Plain text on purpose. There is no markdown rendering and no view/edit split,
+ * so there is no moment where the text on screen is not the text that would be
+ * sent — which is what makes "the agent gets exactly what you see" true rather
+ * than nearly true.
+ */
+export default function NoteEditor({
+  projectId,
+  title,
+  body,
+  onTitleChange,
+  onBodyChange,
+  onCommit,
+  onDelete,
+}: Props) {
+  return (
+    <div className="flex flex-col h-full min-h-0 gap-2 p-3">
+      {/* Wraps rather than overflows. The two buttons are a group with a fixed
+          appetite (~190px) and the title field can shrink only so far, so in a
+          narrow dock the title takes the first row and the buttons the second.
+          Without the wrap the group is simply clipped by the dock's
+          `overflow-hidden`, which puts Delete off-window with no scrollbar to
+          reach it. */}
+      <div className="flex flex-wrap items-center gap-2">
+        <input
+          value={title}
+          onChange={(e) => onTitleChange(e.target.value)}
+          onBlur={onCommit}
+          placeholder="Note title"
+          aria-label="Note title"
+          className="flex-1 min-w-24 px-2 h-8 bg-[var(--bg-primary)] border border-[var(--border-color)] rounded-[var(--radius-control)] text-[13px] text-[var(--text-primary)] focus:border-[var(--accent)] transition-colors"
+        />
+        <div className="flex items-center gap-2 flex-shrink-0">
+          {/* The live editor text, not `note.body` — what is on screen is what
+              gets sent. */}
+          <SendToAgentButton projectId={projectId} body={body} />
+          <Button variant="danger" onClick={onDelete} aria-label="Delete note">
+            Delete
+          </Button>
+        </div>
+      </div>
+      <textarea
+        value={body}
+        onChange={(e) => onBodyChange(e.target.value)}
+        onBlur={onCommit}
+        placeholder="Reminders, gotchas, a prompt worth keeping…"
+        aria-label="Note body"
+        className="flex-1 min-h-0 w-full px-3 py-2 bg-[var(--bg-primary)] border border-[var(--border-color)] rounded-[var(--radius-control)] text-[13px] text-[var(--text-primary)] focus:border-[var(--accent)] resize-none font-mono transition-colors"
+      />
+      <p className="text-xs text-[var(--text-secondary)]">
+        Notes save when a field loses focus. Sending puts the note in the agent&rsquo;s
+        prompt — you press Enter.
+      </p>
+    </div>
+  );
+}

app/src/components/notes/NoteSwitcher.test.tsx

@@ -0,0 +1,115 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { render, screen, fireEvent } from "@testing-library/react";
+import NoteSwitcher from "./NoteSwitcher";
+import type { Note } from "../../lib/types";
+
+const onTitleChange = vi.fn();
+const onCommit = vi.fn();
+const onSelect = vi.fn();
+
+const note = (over: Partial<Note> = {}): Note => ({
+  id: "n1",
+  title: "Deploy steps",
+  body: "",
+  pinned: false,
+  created_at: "2026-09-01T00:00:00Z",
+  updated_at: "2026-09-01T00:00:00Z",
+  ...over,
+});
+
+const setup = (notes: Note[], selectedId = notes[0]?.id ?? "", title = notes[0]?.title ?? "") =>
+  render(
+    <NoteSwitcher
+      notes={notes}
+      selectedId={selectedId}
+      title={title}
+      onTitleChange={onTitleChange}
+      onCommit={onCommit}
+      onSelect={onSelect}
+    />,
+  );
+
+beforeEach(() => vi.clearAllMocks());
+
+describe("NoteSwitcher", () => {
+  it("edits the title in place, committing on blur", () => {
+    setup([note()]);
+    const field = screen.getByLabelText("Note title");
+    expect(field).toHaveValue("Deploy steps");
+
+    fireEvent.change(field, { target: { value: "Deploy steps v2" } });
+    expect(onTitleChange).toHaveBeenCalledWith("Deploy steps v2");
+    expect(onCommit).not.toHaveBeenCalled();
+
+    fireEvent.blur(field);
+    expect(onCommit).toHaveBeenCalledTimes(1);
+  });
+
+  it("keeps the other notes out of the way until asked for", () => {
+    setup([note(), note({ id: "n2", title: "Gotchas" })]);
+    expect(screen.queryByText("Gotchas")).not.toBeInTheDocument();
+
+    fireEvent.click(screen.getByRole("button", { name: /switch note/i }));
+    expect(screen.getByRole("option", { name: "Gotchas" })).toBeInTheDocument();
+  });
+
+  it("reports whether the list is open", () => {
+    setup([note()]);
+    const trigger = screen.getByRole("button", { name: /switch note/i });
+    expect(trigger).toHaveAttribute("aria-expanded", "false");
+
+    fireEvent.click(trigger);
+    expect(trigger).toHaveAttribute("aria-expanded", "true");
+  });
+
+  it("marks the current note as the selected option", () => {
+    setup([note(), note({ id: "n2", title: "Gotchas" })], "n2", "Gotchas");
+    fireEvent.click(screen.getByRole("button", { name: /switch note/i }));
+
+    expect(screen.getByRole("option", { name: "Gotchas" })).toHaveAttribute(
+      "aria-selected",
+      "true",
+    );
+    expect(screen.getByRole("option", { name: "Deploy steps" })).toHaveAttribute(
+      "aria-selected",
+      "false",
+    );
+  });
+
+  it("selects a note and closes", () => {
+    setup([note(), note({ id: "n2", title: "Gotchas" })]);
+    fireEvent.click(screen.getByRole("button", { name: /switch note/i }));
+    fireEvent.click(screen.getByRole("option", { name: "Gotchas" }));
+
+    expect(onSelect).toHaveBeenCalledWith("n2");
+    expect(screen.queryByRole("listbox")).not.toBeInTheDocument();
+  });
+
+  it("names an untitled note rather than showing an empty row", () => {
+    setup([note({ title: "   " })]);
+    fireEvent.click(screen.getByRole("button", { name: /switch note/i }));
+    expect(screen.getByRole("option", { name: "Untitled note" })).toBeInTheDocument();
+  });
+
+  // Notes are addressed by id, never by title. Two untitled notes are the
+  // ordinary case, and a title-keyed list would collapse them into one row.
+  it("lists two notes that share a title as two options", () => {
+    setup([note({ id: "n1", title: "" }), note({ id: "n2", title: "" })]);
+    fireEvent.click(screen.getByRole("button", { name: /switch note/i }));
+
+    const options = screen.getAllByRole("option", { name: "Untitled note" });
+    expect(options).toHaveLength(2);
+
+    fireEvent.click(options[1]);
+    expect(onSelect).toHaveBeenCalledWith("n2");
+  });
+
+  it("closes on Escape without selecting anything", () => {
+    setup([note(), note({ id: "n2", title: "Gotchas" })]);
+    fireEvent.click(screen.getByRole("button", { name: /switch note/i }));
+    fireEvent.keyDown(document, { key: "Escape" });
+
+    expect(screen.queryByRole("listbox")).not.toBeInTheDocument();
+    expect(onSelect).not.toHaveBeenCalled();
+  });
+});

app/src/components/notes/NoteSwitcher.tsx

@@ -0,0 +1,112 @@
+import { useEffect, useRef, useState } from "react";
+import type { Note } from "../../lib/types";
+
+export const UNTITLED = "Untitled note";
+
+interface Props {
+  notes: Note[];
+  selectedId: string;
+  title: string;
+  onTitleChange: (value: string) => void;
+  onCommit: () => void;
+  onSelect: (id: string) => void;
+}
+
+/**
+ * One row that both names the current note and switches to another.
+ *
+ * The dock has no room for a permanent list of titles, so the title field
+ * doubles as the label of what is open and the chevron beside it holds the
+ * rest. Renaming therefore needs no separate affordance.
+ *
+ * Two honest controls rather than one `role="combobox"`: a text field and a
+ * button that opens a listbox. A real combobox owes its listbox keyboard
+ * navigation, active-descendant tracking and an input that filters — none of
+ * which this needs, and half of which is worse than not claiming the role.
+ *
+ * `OverflowMenu` is deliberately not reused here despite the shape being
+ * close. It keys its items by label, and notes are addressed by id: two
+ * untitled notes are the ordinary case and would collapse into one row.
+ */
+export default function NoteSwitcher({
+  notes,
+  selectedId,
+  title,
+  onTitleChange,
+  onCommit,
+  onSelect,
+}: Props) {
+  const [open, setOpen] = useState(false);
+  const rootRef = useRef<HTMLDivElement>(null);
+
+  // Same dismissal contract as `OverflowMenu`, so the two feel identical.
+  useEffect(() => {
+    if (!open) return;
+    const onDocClick = (e: MouseEvent) => {
+      if (!rootRef.current?.contains(e.target as Node)) setOpen(false);
+    };
+    const onKey = (e: KeyboardEvent) => {
+      if (e.key === "Escape") setOpen(false);
+    };
+    document.addEventListener("mousedown", onDocClick);
+    document.addEventListener("keydown", onKey);
+    return () => {
+      document.removeEventListener("mousedown", onDocClick);
+      document.removeEventListener("keydown", onKey);
+    };
+  }, [open]);
+
+  return (
+    <div ref={rootRef} className="relative flex items-center gap-1 min-w-0">
+      <input
+        value={title}
+        onChange={(e) => onTitleChange(e.target.value)}
+        onBlur={onCommit}
+        placeholder="Note title"
+        aria-label="Note title"
+        className="flex-1 min-w-0 px-2 h-7 bg-[var(--bg-primary)] border border-[var(--border-color)] rounded-[var(--radius-control)] text-[13px] text-[var(--text-primary)] focus:border-[var(--accent)] transition-colors"
+      />
+      <button
+        type="button"
+        aria-label="Switch note"
+        aria-haspopup="listbox"
+        aria-expanded={open}
+        onClick={() => setOpen((o) => !o)}
+        className="inline-flex items-center justify-center h-7 w-6 flex-shrink-0 rounded-[var(--radius-control)] border border-[var(--border-color)] bg-[var(--bg-tertiary)] text-[var(--text-secondary)] hover:text-[var(--text-primary)] hover:bg-[var(--border-color)] transition-colors"
+      >
+        <span aria-hidden="true" className="leading-none text-[10px]">▾</span>
+      </button>
+      {open && (
+        <div
+          role="listbox"
+          aria-label="Notes"
+          className="absolute right-0 top-full mt-1 z-40 w-full max-h-64 overflow-y-auto py-1 bg-[var(--bg-overlay)] border border-[var(--border-color)] rounded-[var(--radius-panel)]"
+          style={{ boxShadow: "var(--shadow-overlay)" }}
+        >
+          {/* Buttons directly inside the listbox: wrapping each in an `<li>`
+              would put an implicit `listitem` between the listbox and its
+              options, which is not a child role a listbox owns. */}
+          {notes.map((n) => (
+            <button
+              key={n.id}
+              type="button"
+              role="option"
+              aria-selected={n.id === selectedId}
+              onClick={() => {
+                onSelect(n.id);
+                setOpen(false);
+              }}
+              className={`block w-full text-left px-3 py-1.5 text-xs truncate transition-colors hover:bg-[var(--bg-tertiary)] ${
+                n.id === selectedId
+                  ? "text-[var(--text-primary)] bg-[var(--bg-tertiary)]"
+                  : "text-[var(--text-secondary)]"
+              }`}
+            >
+              {n.title.trim() || UNTITLED}
+            </button>
+          ))}
+        </div>
+      )}
+    </div>
+  );
+}

app/src/components/notes/NotesDockPanel.test.tsx

@@ -0,0 +1,143 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { render, screen, fireEvent, waitFor } from "@testing-library/react";
+import NotesDockPanel from "./NotesDockPanel";
+import type { Note } from "../../lib/types";
+
+const saveNote = vi.fn(async () => true);
+const deleteNote = vi.fn(async () => true);
+const createNote = vi.fn();
+let notes: Note[] = [];
+let loading = false;
+
+vi.mock("../../hooks/useNotes", () => ({
+  useNotes: () => ({
+    notes,
+    loading,
+    saveState: { status: "idle", error: null },
+    createNote,
+    saveNote,
+    deleteNote,
+  }),
+}));
+
+const sendProps: Record<string, unknown>[] = [];
+vi.mock("./SendToAgentButton", () => ({
+  default: (props: Record<string, unknown>) => {
+    sendProps.push(props);
+    return <button type="button">Send to agent</button>;
+  },
+}));
+
+const note = (over: Partial<Note> = {}): Note => ({
+  id: "n1",
+  title: "Deploy steps",
+  body: "one\ntwo",
+  pinned: false,
+  created_at: "2026-09-01T00:00:00Z",
+  updated_at: "2026-09-01T00:00:00Z",
+  ...over,
+});
+
+beforeEach(() => {
+  vi.clearAllMocks();
+  sendProps.length = 0;
+  notes = [];
+  loading = false;
+});
+
+describe("NotesDockPanel", () => {
+  it("says it is loading rather than flashing an empty state", () => {
+    loading = true;
+    render(<NotesDockPanel projectId="p1" />);
+    expect(screen.getByText(/loading notes/i)).toBeInTheDocument();
+  });
+
+  it("offers a first note when the project has none", async () => {
+    render(<NotesDockPanel projectId="p1" />);
+    fireEvent.click(screen.getByRole("button", { name: /new note/i }));
+    await waitFor(() => expect(createNote).toHaveBeenCalled());
+  });
+
+  // The point of the redesign: the dock spends its height on the note being
+  // written, not on a permanent list of the ones that are not.
+  it("shows one note at a time, the rest behind the switcher", () => {
+    notes = [note(), note({ id: "n2", title: "Gotchas" })];
+    render(<NotesDockPanel projectId="p1" />);
+
+    expect(screen.getByLabelText("Note title")).toHaveValue("Deploy steps");
+    expect(screen.queryByText("Gotchas")).not.toBeInTheDocument();
+
+    fireEvent.click(screen.getByRole("button", { name: /switch note/i }));
+    expect(screen.getByRole("option", { name: "Gotchas" })).toBeInTheDocument();
+  });
+
+  it("switches to the note picked from the list", () => {
+    notes = [note(), note({ id: "n2", title: "Gotchas", body: "careful" })];
+    render(<NotesDockPanel projectId="p1" />);
+
+    fireEvent.click(screen.getByRole("button", { name: /switch note/i }));
+    fireEvent.click(screen.getByRole("option", { name: "Gotchas" }));
+
+    expect(screen.getByLabelText("Note title")).toHaveValue("Gotchas");
+    expect(screen.getByLabelText("Note body")).toHaveValue("careful");
+  });
+
+  it("saves the body when it loses focus, and not before", () => {
+    notes = [note()];
+    render(<NotesDockPanel projectId="p1" />);
+    const body = screen.getByLabelText("Note body");
+
+    fireEvent.change(body, { target: { value: "one\ntwo\nthree" } });
+    expect(saveNote).not.toHaveBeenCalled();
+
+    fireEvent.blur(body);
+    expect(saveNote).toHaveBeenCalledWith(
+      expect.objectContaining({ id: "n1", body: "one\ntwo\nthree" }),
+    );
+  });
+
+  it("keeps New and Delete in the overflow menu, out of the writing area", async () => {
+    notes = [note()];
+    render(<NotesDockPanel projectId="p1" />);
+    fireEvent.click(screen.getByRole("button", { name: /note actions/i }));
+
+    fireEvent.click(screen.getByRole("menuitem", { name: /delete note/i }));
+    await waitFor(() => expect(deleteNote).toHaveBeenCalledWith("n1"));
+  });
+
+  it("opens the note it just created", async () => {
+    notes = [note()];
+    createNote.mockResolvedValueOnce(note({ id: "n9", title: "" }));
+    const view = render(<NotesDockPanel projectId="p1" />);
+
+    fireEvent.click(screen.getByRole("button", { name: /note actions/i }));
+    fireEvent.click(screen.getByRole("menuitem", { name: /new note/i }));
+    await waitFor(() => expect(createNote).toHaveBeenCalled());
+
+    notes = [note(), note({ id: "n9", title: "" })];
+    view.rerender(<NotesDockPanel projectId="p1" />);
+    await waitFor(() =>
+      expect(screen.getByLabelText("Note title")).toHaveValue(""),
+    );
+  });
+
+  // The send bar sits on the dock's bottom edge, inside an `overflow-hidden`
+  // panel, so both of these are load-bearing rather than cosmetic.
+  it("sends from a full-width bar whose menu opens upward", () => {
+    notes = [note()];
+    render(<NotesDockPanel projectId="p1" />);
+
+    expect(screen.getByRole("button", { name: /send to agent/i })).toBeInTheDocument();
+    expect(sendProps.at(-1)).toMatchObject({ fullWidth: true, dropUp: true });
+  });
+
+  it("sends what is on screen, not what was last saved", () => {
+    notes = [note()];
+    render(<NotesDockPanel projectId="p1" />);
+    fireEvent.change(screen.getByLabelText("Note body"), {
+      target: { value: "edited but not blurred" },
+    });
+
+    expect(sendProps.at(-1)).toMatchObject({ body: "edited but not blurred" });
+  });
+});

app/src/components/notes/NotesDockPanel.tsx

@@ -0,0 +1,119 @@
+import { useMemo, useState } from "react";
+import { useNotes } from "../../hooks/useNotes";
+import { useNoteDraft } from "./useNoteDraft";
+import NoteSwitcher from "./NoteSwitcher";
+import SendToAgentButton from "./SendToAgentButton";
+import Button from "../ui/Button";
+import OverflowMenu from "../ui/OverflowMenu";
+import SaveIndicator from "../ui/SaveIndicator";
+
+interface Props {
+  projectId: string;
+}
+
+/**
+ * Notes at dock width.
+ *
+ * Deliberately not `NotesPanel` in a narrower box. The tab can afford a column
+ * of titles beside the editor; the dock cannot, and shrinking that layout
+ * spends its height on chrome — a title strip, a wrapped button row and a
+ * paragraph of help — for a body that ends up a few words wide.
+ *
+ * So the dock shows exactly one note. The title row names it and switches to
+ * another, the actions that are not writing live in the overflow menu, and
+ * everything left over is the body. Roughly 240px of height comes back.
+ *
+ * What the two surfaces share is the part that must not drift: `useNotes` for
+ * the cache and its write ordering, and `useNoteDraft` for when a keystroke
+ * becomes a save. Only the layout is different.
+ */
+export default function NotesDockPanel({ projectId }: Props) {
+  const { notes, loading, saveState, createNote, saveNote, deleteNote } =
+    useNotes(projectId);
+  const [selectedId, setSelectedId] = useState<string | null>(null);
+
+  const selected = useMemo(
+    () => notes.find((n) => n.id === selectedId) ?? notes[0] ?? null,
+    [notes, selectedId],
+  );
+
+  const { title, body, setTitle, setBody, commit } = useNoteDraft(
+    selected,
+    saveNote,
+  );
+
+  const onCreate = async () => {
+    const note = await createNote();
+    if (note) setSelectedId(note.id);
+  };
+
+  if (loading) {
+    return (
+      <p className="p-4 text-xs text-[var(--text-secondary)]">Loading notes…</p>
+    );
+  }
+
+  if (!selected) {
+    return (
+      <div className="flex-1 flex flex-col items-center justify-center gap-3 p-4">
+        <p className="text-[13px] text-[var(--text-secondary)] text-center">
+          Keep reminders here, and send any of them straight to a running Claude
+          session.
+        </p>
+        <Button variant="primary" onClick={onCreate}>
+          New note
+        </Button>
+      </div>
+    );
+  }
+
+  return (
+    <div className="flex flex-col h-full min-h-0">
+      <div className="flex items-center gap-1 px-2 py-1.5 flex-shrink-0 border-b border-[var(--border-color)]">
+        <div className="flex-1 min-w-0">
+          <NoteSwitcher
+            notes={notes}
+            selectedId={selected.id}
+            title={title}
+            onTitleChange={setTitle}
+            onCommit={commit}
+            onSelect={setSelectedId}
+          />
+        </div>
+        {/* Renders nothing while idle, so it costs no width until it matters. */}
+        <SaveIndicator state={saveState} />
+        <OverflowMenu
+          label="Note actions"
+          items={[
+            { label: "New note", onSelect: () => void onCreate() },
+            {
+              label: "Delete note",
+              danger: true,
+              onSelect: () => void deleteNote(selected.id),
+            },
+          ]}
+        />
+      </div>
+
+      <textarea
+        value={body}
+        onChange={(e) => setBody(e.target.value)}
+        onBlur={commit}
+        placeholder="Reminders, gotchas, a prompt worth keeping…"
+        aria-label="Note body"
+        className="flex-1 min-h-0 w-full px-3 py-2 bg-transparent text-[13px] text-[var(--text-primary)] resize-none font-mono"
+      />
+
+      <div className="px-2 py-2 flex-shrink-0 border-t border-[var(--border-color)]">
+        {/* The live draft, not `selected.body` — what is on screen is what gets
+            sent. `dropUp` because the dock clips its own overflow. */}
+        <SendToAgentButton
+          projectId={projectId}
+          body={body}
+          fullWidth
+          dropUp
+        />
+      </div>
+    </div>
+  );
+}

app/src/components/notes/NotesPanel.shared.test.tsx

@@ -0,0 +1,175 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { render, screen, within, fireEvent, waitFor } from "@testing-library/react";
+import NotesPanel from "./NotesPanel";
+import NotesDockPanel from "./NotesDockPanel";
+import { useAppState } from "../../store/appState";
+import type { Note } from "../../lib/types";
+
+/**
+ * Two panels, one project — the configuration the app actually runs in.
+ *
+ * `NotesTab` mounts a `NotesPanel` and `NotesDock` mounts a `NotesDockPanel`,
+ * and the dock follows the active tab's project, so opening the dock over a
+ * Project Home tab mounts both for the *same* project. Every other notes test
+ * mounts exactly one, which is precisely the configuration in which a
+ * per-panel cache looks correct: it is only with two that an edit made in one
+ * is seen — or lost — by the other. `useNotes` is deliberately **not** mocked
+ * here; the cache is what is under test.
+ *
+ * The two are different components on purpose, which is exactly why this test
+ * pairs them rather than mounting the same one twice: the layouts diverged,
+ * and the cache and draft rules they share are what must not.
+ */
+
+const files: Record<string, Note[]> = {};
+
+vi.mock("../../lib/tauri-commands", () => ({
+  listNotes: async (p: string) => [...(files[p] ?? [])],
+  saveNote: async (p: string, n: Note) => {
+    const list = files[p] ?? (files[p] = []);
+    const at = list.findIndex((x) => x.id === n.id);
+    if (at === -1) list.unshift(n);
+    else list[at] = n;
+    return n;
+  },
+  deleteNote: async (p: string, id: string) => {
+    files[p] = (files[p] ?? []).filter((x) => x.id !== id);
+  },
+}));
+
+vi.mock("./SendToAgentButton", () => ({
+  default: () => <button type="button">Send to agent</button>,
+}));
+
+const note = (over: Partial<Note> = {}): Note => ({
+  id: "n1",
+  title: "Deploy steps",
+  body: "one",
+  pinned: false,
+  created_at: "2026-09-01T00:00:00Z",
+  updated_at: "2026-09-01T00:00:00Z",
+  ...over,
+});
+
+/** The tab and the dock, mounted together the way `App` mounts them. */
+function renderBothSurfaces() {
+  render(
+    <>
+      <div data-testid="tab">
+        <NotesPanel projectId="p1" />
+      </div>
+      <div data-testid="dock">
+        <NotesDockPanel projectId="p1" />
+      </div>
+    </>,
+  );
+  return {
+    tab: () => within(screen.getByTestId("tab")),
+    dock: () => within(screen.getByTestId("dock")),
+  };
+}
+
+beforeEach(() => {
+  for (const key of Object.keys(files)) delete files[key];
+  files.p1 = [note()];
+  useAppState.setState({ notesByProject: {}, notesLoading: {}, toasts: [] });
+});
+
+describe("the tab and the dock both open on one project", () => {
+  it("shows an edit made in one surface in the other", async () => {
+    const { tab, dock } = renderBothSurfaces();
+    await waitFor(() => expect(tab().getByLabelText("Note body")).toHaveValue("one"));
+
+    const dockTitle = dock().getByLabelText("Note title");
+    fireEvent.change(dockTitle, { target: { value: "Deploy steps v2" } });
+    fireEvent.blur(dockTitle);
+
+    // The other surface's list *and* its editor, not just one of them.
+    await waitFor(() =>
+      expect(tab().getByRole("button", { name: /deploy steps v2/i })).toBeInTheDocument(),
+    );
+    expect(tab().getByLabelText("Note title")).toHaveValue("Deploy steps v2");
+  });
+
+  it("does not write one surface's stale copy over the other's edit", async () => {
+    // The reported repro: edit in the dock, then go back to the tab and edit
+    // there. With a cache per panel, the tab committed `{...staleNote, ...}`
+    // and the dock's edit was gone from disk with no error and no indicator.
+    const { tab, dock } = renderBothSurfaces();
+    await waitFor(() => expect(tab().getByLabelText("Note body")).toHaveValue("one"));
+
+    const dockTitle = dock().getByLabelText("Note title");
+    fireEvent.change(dockTitle, { target: { value: "Deploy steps v2" } });
+    fireEvent.blur(dockTitle);
+    await waitFor(() => expect(files.p1[0].title).toBe("Deploy steps v2"));
+
+    const tabBody = tab().getByLabelText("Note body");
+    fireEvent.change(tabBody, { target: { value: "two" } });
+    fireEvent.blur(tabBody);
+
+    await waitFor(() => expect(files.p1[0].body).toBe("two"));
+    expect(files.p1).toHaveLength(1);
+    expect(files.p1[0].title).toBe("Deploy steps v2");
+  });
+
+  it("reads the project once for both surfaces", async () => {
+    // Two panels are two `useNotes`, but the in-flight flag is per project, so
+    // mounting the dock over an open Notes tab does not re-read the file.
+    const listNotes = vi.spyOn(
+      await import("../../lib/tauri-commands"),
+      "listNotes",
+    );
+    renderBothSurfaces();
+    await waitFor(() =>
+      expect(screen.getAllByLabelText("Note body")[0]).toHaveValue("one"),
+    );
+    expect(listNotes).toHaveBeenCalledTimes(1);
+    listNotes.mockRestore();
+  });
+
+  it("keeps text the user is part-way through typing when the other surface saves", async () => {
+    // Showing a remote edit must never mean discarding an unsaved local one.
+    const { tab, dock } = renderBothSurfaces();
+    await waitFor(() => expect(tab().getByLabelText("Note body")).toHaveValue("one"));
+
+    const tabBody = tab().getByLabelText("Note body");
+    fireEvent.change(tabBody, { target: { value: "half-typed" } });
+
+    const dockBody = dock().getByLabelText("Note body");
+    fireEvent.change(dockBody, { target: { value: "saved in the dock" } });
+    fireEvent.blur(dockBody);
+    await waitFor(() => expect(files.p1[0].body).toBe("saved in the dock"));
+
+    expect(tabBody).toHaveValue("half-typed");
+  });
+
+  it("falls back to another note when the selected one is deleted", async () => {
+    // The claim a differently-named test in NotesPanel.test.tsx used to make
+    // and could not keep: `useNotes` is mocked there and its list never
+    // changes, so the fallback was invisible. Here the list is real.
+    files.p1 = [note(), note({ id: "n2", title: "Gotchas", body: "beware" })];
+    const { tab } = renderBothSurfaces();
+    await waitFor(() => expect(tab().getByLabelText("Note body")).toHaveValue("one"));
+
+    fireEvent.click(tab().getByRole("button", { name: /delete note/i }));
+
+    await waitFor(() => expect(tab().getByLabelText("Note body")).toHaveValue("beware"));
+    expect(tab().queryByRole("button", { name: /deploy steps/i })).not.toBeInTheDocument();
+    expect(files.p1).toHaveLength(1);
+  });
+
+  it("shows a note created in one surface in the other", async () => {
+    const { tab, dock } = renderBothSurfaces();
+    await waitFor(() => expect(tab().getByLabelText("Note body")).toHaveValue("one"));
+
+    // The dock keeps New behind its overflow menu — its height belongs to the
+    // note being written, not to a button row.
+    fireEvent.click(dock().getByRole("button", { name: /note actions/i }));
+    fireEvent.click(dock().getByRole("menuitem", { name: /new note/i }));
+
+    await waitFor(() =>
+      expect(tab().getAllByRole("button", { name: /untitled note/i })).toHaveLength(1),
+    );
+    expect(files.p1).toHaveLength(2);
+  });
+});

app/src/components/notes/NotesPanel.test.tsx

@@ -0,0 +1,112 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { render, screen, fireEvent, waitFor } from "@testing-library/react";
+import NotesPanel from "./NotesPanel";
+import type { Note } from "../../lib/types";
+
+const saveNote = vi.fn(async () => true);
+const deleteNote = vi.fn(async () => true);
+const createNote = vi.fn();
+let notes: Note[] = [];
+let loading = false;
+
+vi.mock("../../hooks/useNotes", () => ({
+  useNotes: () => ({
+    notes,
+    loading,
+    saveState: { status: "idle", error: null },
+    createNote,
+    saveNote,
+    deleteNote,
+  }),
+}));
+
+vi.mock("./SendToAgentButton", () => ({
+  default: ({ body }: { body: string }) => (
+    <button type="button" data-testid="send">{`send:${body}`}</button>
+  ),
+}));
+
+const note = (over: Partial<Note> = {}): Note => ({
+  id: "n1",
+  title: "Deploy steps",
+  body: "one\ntwo",
+  pinned: false,
+  created_at: "2026-09-01T00:00:00Z",
+  updated_at: "2026-09-01T00:00:00Z",
+  ...over,
+});
+
+beforeEach(() => {
+  vi.clearAllMocks();
+  notes = [];
+  loading = false;
+});
+
+describe("NotesPanel", () => {
+  it("invites the user to start when there are no notes", () => {
+    render(<NotesPanel projectId="p1" />);
+    expect(screen.getByText(/no notes yet/i)).toBeInTheDocument();
+  });
+
+  it("lists notes by title and selects the first", () => {
+    notes = [note(), note({ id: "n2", title: "Gotchas" })];
+    render(<NotesPanel projectId="p1" />);
+    expect(screen.getByRole("button", { name: /deploy steps/i })).toBeInTheDocument();
+    expect(screen.getByLabelText("Note body")).toHaveValue("one\ntwo");
+  });
+
+  it("shows an untitled note under a placeholder rather than a blank row", () => {
+    notes = [note({ title: "" })];
+    render(<NotesPanel projectId="p1" />);
+    expect(screen.getByRole("button", { name: /untitled note/i })).toBeInTheDocument();
+  });
+
+  it("switches the editor when another note is selected", () => {
+    notes = [note(), note({ id: "n2", title: "Gotchas", body: "beware" })];
+    render(<NotesPanel projectId="p1" />);
+    fireEvent.click(screen.getByRole("button", { name: /gotchas/i }));
+    expect(screen.getByLabelText("Note body")).toHaveValue("beware");
+  });
+
+  it("saves on blur, not on every keystroke", async () => {
+    notes = [note()];
+    render(<NotesPanel projectId="p1" />);
+    const body = screen.getByLabelText("Note body");
+
+    fireEvent.change(body, { target: { value: "edited" } });
+    expect(saveNote).not.toHaveBeenCalled();
+
+    fireEvent.blur(body);
+    await waitFor(() => expect(saveNote).toHaveBeenCalledWith(
+      expect.objectContaining({ id: "n1", body: "edited" }),
+    ));
+  });
+
+  it("does not save on blur when nothing changed", async () => {
+    // Clicking through notes to read them must not write the file.
+    notes = [note()];
+    render(<NotesPanel projectId="p1" />);
+    fireEvent.blur(screen.getByLabelText("Note body"));
+    await waitFor(() => expect(saveNote).not.toHaveBeenCalled());
+  });
+
+  it("hands the live editor text to the send button, not the last saved copy", () => {
+    // Sending what is on screen is the whole contract: no transform on the way
+    // out except the newline substitution.
+    notes = [note()];
+    render(<NotesPanel projectId="p1" />);
+    fireEvent.change(screen.getByLabelText("Note body"), { target: { value: "fresh" } });
+    expect(screen.getByTestId("send")).toHaveTextContent("send:fresh");
+  });
+
+  it("asks the hook to delete the selected note", async () => {
+    // Only the call: `useNotes` is mocked here and the mocked list never
+    // changes, so nothing in this file can exercise what the panel selects
+    // afterwards. The fallback is covered against the real hook in
+    // NotesPanel.shared.test.tsx.
+    notes = [note(), note({ id: "n2", title: "Gotchas" })];
+    render(<NotesPanel projectId="p1" />);
+    fireEvent.click(screen.getByRole("button", { name: /delete note/i }));
+    await waitFor(() => expect(deleteNote).toHaveBeenCalledWith("n1"));
+  });
+});

app/src/components/notes/NotesPanel.tsx

@@ -0,0 +1,115 @@
+import { useMemo, useState } from "react";
+import { useNotes } from "../../hooks/useNotes";
+import { useNoteDraft } from "./useNoteDraft";
+import NoteEditor from "./NoteEditor";
+import Button from "../ui/Button";
+import SaveIndicator from "../ui/SaveIndicator";
+
+interface Props {
+  projectId: string;
+}
+
+const UNTITLED = "Untitled note";
+
+/**
+ * The notes surface itself, shared by the Project Home tab and the dock so the
+ * two cannot drift into different behaviour.
+ *
+ * Master/detail: titles beside the editor when there is room, stacked above it
+ * when there is not. That is a **container** query, not a viewport one, because
+ * the two surfaces differ in width while sharing a viewport — the dock opens at
+ * 352px and the tab is the width of the main area. A `md:` breakpoint would
+ * read the window and give both the same answer, which is the wrong answer for
+ * one of them.
+ *
+ * The threshold is arithmetic, not taste: side by side needs the 192px list,
+ * plus an editor wide enough for its own action row (~280px), plus the divider.
+ * Below ~473px the editor is narrower than its buttons, so `@lg` (512px) is the
+ * first stop that clears it.
+ *
+ * The editor holds draft text locally and commits on blur, which is how every
+ * other editable field in the app behaves (`ClaudeInstructionsEditor`, the
+ * Config tab).
+ */
+export default function NotesPanel({ projectId }: Props) {
+  const { notes, loading, saveState, createNote, saveNote, deleteNote } =
+    useNotes(projectId);
+  const [selectedId, setSelectedId] = useState<string | null>(null);
+
+  const selected = useMemo(
+    () => notes.find((n) => n.id === selectedId) ?? notes[0] ?? null,
+    [notes, selectedId],
+  );
+
+  const { title, body, setTitle, setBody, commit } = useNoteDraft(
+    selected,
+    saveNote,
+  );
+
+  const onCreate = async () => {
+    const note = await createNote();
+    if (note) setSelectedId(note.id);
+  };
+
+  if (loading) {
+    return (
+      <p className="p-4 text-xs text-[var(--text-secondary)]">Loading notes…</p>
+    );
+  }
+
+  return (
+    <div className="@container flex flex-col h-full min-h-0">
+      <div className="flex items-center justify-between gap-2 px-3 py-2 border-b border-[var(--border-color)]">
+        <Button variant="primary" onClick={onCreate}>
+          New note
+        </Button>
+        <SaveIndicator state={saveState} />
+      </div>
+
+      {notes.length === 0 ? (
+        <div className="flex-1 flex items-center justify-center p-4">
+          <p className="text-[13px] text-[var(--text-secondary)] text-center">
+            No notes yet. Keep reminders here, and send any of them straight to a
+            running Claude session.
+          </p>
+        </div>
+      ) : (
+        <div className="flex-1 min-h-0 flex flex-col @lg:flex-row">
+          {/* Stacked: a capped strip of titles above the editor, so the note
+              being written keeps most of the height. Side by side: a full-height
+              column of the fixed width the editor's arithmetic assumes. */}
+          <ul className="flex-shrink-0 overflow-y-auto py-1 max-h-32 border-b @lg:max-h-none @lg:w-48 @lg:border-b-0 @lg:border-r border-[var(--border-color)]">
+            {notes.map((n) => (
+              <li key={n.id}>
+                <button
+                  type="button"
+                  onClick={() => setSelectedId(n.id)}
+                  className={`w-full text-left px-3 py-1.5 text-xs truncate transition-colors ${
+                    selected?.id === n.id
+                      ? "bg-[var(--bg-tertiary)] text-[var(--text-primary)]"
+                      : "text-[var(--text-secondary)] hover:text-[var(--text-primary)]"
+                  }`}
+                >
+                  {n.title.trim() || UNTITLED}
+                </button>
+              </li>
+            ))}
+          </ul>
+          <div className="flex-1 min-w-0">
+            {selected && (
+              <NoteEditor
+                projectId={projectId}
+                title={title}
+                body={body}
+                onTitleChange={setTitle}
+                onBodyChange={setBody}
+                onCommit={commit}
+                onDelete={() => void deleteNote(selected.id)}
+              />
+            )}
+          </div>
+        </div>
+      )}
+    </div>
+  );
+}

app/src/components/notes/SendToAgentButton.test.tsx

@@ -0,0 +1,191 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { render, screen, fireEvent, waitFor } from "@testing-library/react";
+import SendToAgentButton from "./SendToAgentButton";
+import type { Project, TerminalSession } from "../../lib/types";
+
+const sendInput = vi.fn(async () => {});
+let sessions: TerminalSession[] = [];
+
+vi.mock("../../hooks/useTerminal", () => ({
+  useTerminal: () => ({ sessions, sendInput }),
+}));
+
+const setActiveTabKey = vi.fn();
+const requestTerminalFocus = vi.fn();
+const pushToast = vi.fn();
+let projects: Project[] = [];
+
+vi.mock("../../store/appState", () => ({
+  useAppState: Object.assign(
+    (selector: (s: unknown) => unknown) =>
+      selector({ projects, setActiveTabKey, requestTerminalFocus, pushToast }),
+    {
+      getState: () => ({
+        projects,
+        setActiveTabKey,
+        requestTerminalFocus,
+        pushToast,
+      }),
+    },
+  ),
+  terminalTabKey: (id: string) => `term:${id}`,
+}));
+
+const session = (over: Partial<TerminalSession> = {}): TerminalSession => ({
+  id: "s1",
+  projectId: "p1",
+  projectName: "api",
+  sessionType: "claude",
+  sessionName: null,
+  ...over,
+});
+
+beforeEach(() => {
+  vi.clearAllMocks();
+  sessions = [];
+  projects = [{ id: "p1", name: "api", renamed_session_names: {} } as unknown as Project];
+});
+
+describe("SendToAgentButton", () => {
+  // Unavailable, not `disabled`: the reason a note cannot be sent is the whole
+  // content of these states, and native `disabled` announces it to nobody.
+  it("says why it cannot send when the project has no running session", () => {
+    render(<SendToAgentButton projectId="p1" body="hello" />);
+    const button = screen.getByRole("button", { name: /send to agent/i });
+    expect(button).toHaveAttribute("aria-disabled", "true");
+    expect(button).toHaveAccessibleDescription(
+      "No running Claude session for this project",
+    );
+  });
+
+  it("says why it cannot send an empty note", () => {
+    sessions = [session()];
+    render(<SendToAgentButton projectId="p1" body="   " />);
+    expect(
+      screen.getByRole("button", { name: /send to agent/i }),
+    ).toHaveAccessibleDescription("Nothing to send — this note is empty");
+  });
+
+  it("is unavailable when the only session belongs to another project", () => {
+    sessions = [session({ projectId: "other" })];
+    render(<SendToAgentButton projectId="p1" body="hello" />);
+    expect(
+      screen.getByRole("button", { name: /send to agent/i }),
+    ).toHaveAttribute("aria-disabled", "true");
+  });
+
+  it("is unavailable when the only session is a bash tab", () => {
+    // `bash -l`'s readline has no binding for ESC+CR and just bells, so a
+    // shell is never a target.
+    sessions = [session({ sessionType: "bash" })];
+    render(<SendToAgentButton projectId="p1" body="hello" />);
+    expect(
+      screen.getByRole("button", { name: /send to agent/i }),
+    ).toHaveAttribute("aria-disabled", "true");
+  });
+
+  // `aria-disabled` is advisory — it blocks nothing on its own. Without the
+  // guard this swap would turn a greyed-out button into a live one.
+  it("sends nothing when activated while unavailable", () => {
+    render(<SendToAgentButton projectId="p1" body="hello" />);
+    const button = screen.getByRole("button", { name: /send to agent/i });
+
+    fireEvent.click(button);
+    fireEvent.keyDown(button, { key: "Enter" });
+    fireEvent.keyDown(button, { key: " " });
+
+    expect(sendInput).not.toHaveBeenCalled();
+    expect(screen.queryByRole("menu")).not.toBeInTheDocument();
+  });
+
+  it("sends straight to the one session, with newlines converted and no terminator", async () => {
+    sessions = [session()];
+    render(<SendToAgentButton projectId="p1" body={"one\ntwo"} />);
+
+    fireEvent.click(screen.getByRole("button", { name: /send to agent/i }));
+
+    await waitFor(() => expect(sendInput).toHaveBeenCalledWith("s1", "one\x1b\rtwo"));
+    expect(sendInput.mock.calls[0][1].endsWith("\r")).toBe(false);
+  });
+
+  it("focuses the terminal it sent to, so the user watches it land", async () => {
+    sessions = [session()];
+    render(<SendToAgentButton projectId="p1" body="hi" />);
+    fireEvent.click(screen.getByRole("button", { name: /send to agent/i }));
+    await waitFor(() => expect(setActiveTabKey).toHaveBeenCalledWith("term:s1"));
+  });
+
+  it("offers a menu of display names when several sessions are open", async () => {
+    sessions = [session(), session({ id: "s2", sessionName: "review" })];
+    projects = [
+      { id: "p1", name: "api", renamed_session_names: { s1: "release" } } as unknown as Project,
+    ];
+    render(<SendToAgentButton projectId="p1" body="hi" />);
+
+    fireEvent.click(screen.getByRole("button", { name: /send to agent/i }));
+    expect(sendInput).not.toHaveBeenCalled();
+
+    fireEvent.click(await screen.findByRole("menuitem", { name: "api: release" }));
+    await waitFor(() => expect(sendInput).toHaveBeenCalledWith("s1", "hi"));
+  });
+
+  it("reports a failed send rather than looking like it worked", async () => {
+    sessions = [session()];
+    sendInput.mockRejectedValueOnce(new Error("session closed"));
+    render(<SendToAgentButton projectId="p1" body="hi" />);
+    fireEvent.click(screen.getByRole("button", { name: /send to agent/i }));
+    await waitFor(() => expect(pushToast).toHaveBeenCalled());
+  });
+
+  it("does nothing for an empty note", () => {
+    sessions = [session()];
+    render(<SendToAgentButton projectId="p1" body="   " />);
+    const button = screen.getByRole("button", { name: /send to agent/i });
+    expect(button).toHaveAttribute("aria-disabled", "true");
+
+    fireEvent.click(button);
+    fireEvent.keyDown(button, { key: "Enter" });
+    expect(sendInput).not.toHaveBeenCalled();
+  });
+
+  it("opens the session menu upward when it sits at the foot of the dock", async () => {
+    sessions = [session({ id: "s1" }), session({ id: "s2" })];
+    render(<SendToAgentButton projectId="p1" body="hello" dropUp />);
+    fireEvent.click(screen.getByRole("button", { name: /send to agent/i }));
+
+    // Anchored to the button's top edge, not below it: the dock clips its own
+    // overflow, so a downward menu at the bottom edge is invisible.
+    await waitFor(() => expect(screen.getByRole("menu")).toHaveClass("bottom-full"));
+  });
+
+  // Switching to the tab is not enough. When the dock is open beside the
+  // terminal it sends to, that terminal is already the active tab, so
+  // `setActiveTabKey` changes nothing and no effect re-runs — leaving focus on
+  // this button, one click short of the Enter the user came to press.
+  it("hands focus to the terminal so the next keystroke is Enter", async () => {
+    sessions = [session()];
+    render(<SendToAgentButton projectId="p1" body="hello" />);
+    fireEvent.click(screen.getByRole("button", { name: /send to agent/i }));
+
+    await waitFor(() => expect(requestTerminalFocus).toHaveBeenCalledWith("s1"));
+  });
+
+  it("leaves focus alone when the send failed", async () => {
+    sessions = [session()];
+    sendInput.mockRejectedValueOnce(new Error("pty gone"));
+    render(<SendToAgentButton projectId="p1" body="hello" />);
+    fireEvent.click(screen.getByRole("button", { name: /send to agent/i }));
+
+    await waitFor(() => expect(pushToast).toHaveBeenCalled());
+    expect(requestTerminalFocus).not.toHaveBeenCalled();
+  });
+
+  it("focuses the session picked from the menu, not the first one", async () => {
+    sessions = [session(), session({ id: "s2", sessionName: "review" })];
+    render(<SendToAgentButton projectId="p1" body="hello" />);
+    fireEvent.click(screen.getByRole("button", { name: /send to agent/i }));
+    fireEvent.click(await screen.findByRole("menuitem", { name: "review" }));
+
+    await waitFor(() => expect(requestTerminalFocus).toHaveBeenCalledWith("s2"));
+  });
+});

app/src/components/notes/SendToAgentButton.tsx

@@ -0,0 +1,168 @@
+import { useCallback, useEffect, useMemo, useRef, useState } from "react";
+import { useShallow } from "zustand/react/shallow";
+import { useTerminal } from "../../hooks/useTerminal";
+import { useAppState, terminalTabKey } from "../../store/appState";
+import { toClaudePayload } from "../../lib/claudeInput";
+import { sessionDisplayName } from "../../lib/sessionName";
+import Button from "../ui/Button";
+
+interface Props {
+  projectId: string;
+  body: string;
+  /**
+   * Open the session menu above the button instead of below. The dock puts
+   * this at its foot, and the dock clips its own overflow, so a downward menu
+   * there is drawn outside the panel and never seen.
+   */
+  dropUp?: boolean;
+  /** Fill the row. The dock's send bar is the width of the dock. */
+  fullWidth?: boolean;
+}
+
+/**
+ * Puts a note into a running Claude session's prompt.
+ *
+ * Three behaviours by target count: none disables the button, one sends
+ * straight there, several ask which. It never guesses — the note goes to a
+ * session the user named, or to the only one there is.
+ *
+ * Only `claude` sessions are offered. A bash tab would receive ESC+CR as an
+ * unbound readline key and answer with a bell (see `lib/claudeInput.ts`).
+ */
+export default function SendToAgentButton({
+  projectId,
+  body,
+  dropUp = false,
+  fullWidth = false,
+}: Props) {
+  const { sessions, sendInput } = useTerminal();
+  const { projects, setActiveTabKey, requestTerminalFocus, pushToast } =
+    useAppState(
+      useShallow((s) => ({
+        projects: s.projects,
+        setActiveTabKey: s.setActiveTabKey,
+        requestTerminalFocus: s.requestTerminalFocus,
+        pushToast: s.pushToast,
+      })),
+    );
+  const [menuOpen, setMenuOpen] = useState(false);
+  const rootRef = useRef<HTMLDivElement>(null);
+
+  const targets = useMemo(
+    () =>
+      sessions.filter(
+        (s) => s.projectId === projectId && s.sessionType === "claude",
+      ),
+    [sessions, projectId],
+  );
+
+  const project = projects.find((p) => p.id === projectId);
+  const hasBody = body.trim().length > 0;
+  const unavailable = targets.length === 0 || !hasBody;
+
+  // Same dismissal contract as `ui/OverflowMenu` and the tab context menu.
+  useEffect(() => {
+    if (!menuOpen) return;
+    const onDocClick = (e: MouseEvent) => {
+      if (!rootRef.current?.contains(e.target as Node)) setMenuOpen(false);
+    };
+    const onKey = (e: KeyboardEvent) => {
+      if (e.key === "Escape") setMenuOpen(false);
+    };
+    document.addEventListener("mousedown", onDocClick);
+    document.addEventListener("keydown", onKey);
+    return () => {
+      document.removeEventListener("mousedown", onDocClick);
+      document.removeEventListener("keydown", onKey);
+    };
+  }, [menuOpen]);
+
+  const send = useCallback(
+    async (sessionId: string) => {
+      setMenuOpen(false);
+      try {
+        // No trailing CR: the note lands in the prompt and the user presses
+        // Enter. Newlines become ESC+CR so it arrives as one message rather
+        // than one prompt per line.
+        await sendInput(sessionId, toClaudePayload(body));
+        // A courtesy, not part of the send: if the tab cannot be focused the
+        // text still went.
+        setActiveTabKey(terminalTabKey(sessionId));
+        // Switching tabs is not the same as taking focus, and when the dock is
+        // open beside the terminal it just sent to, that tab is already the
+        // active one — so nothing above moves the caret off this button. The
+        // note is sitting in the prompt waiting for Enter; put the user there.
+        requestTerminalFocus(sessionId);
+      } catch (e) {
+        pushToast({
+          kind: "error",
+          message: "Could not send the note to the agent",
+          detail: String(e),
+        });
+      }
+    },
+    [body, sendInput, setActiveTabKey, requestTerminalFocus, pushToast],
+  );
+
+  const onClick = useCallback(() => {
+    // The target is resolved at click time and pinned for the whole send, the
+    // hazard `useSTT` guards against by capturing its session at record start:
+    // the list can change while the request is in flight.
+    if (targets.length === 1) {
+      void send(targets[0].id);
+      return;
+    }
+    setMenuOpen((open) => !open);
+  }, [targets, send]);
+
+  const title = !hasBody
+    ? "Nothing to send — this note is empty"
+    : targets.length === 0
+      ? "No running Claude session for this project"
+      : "Put this note into the agent's prompt (you press Enter)";
+
+  return (
+    <div
+      ref={rootRef}
+      className={`relative ${fullWidth ? "block w-full" : "inline-block"}`}
+    >
+      <Button
+        variant="secondary"
+        size={fullWidth ? "md" : "sm"}
+        className={fullWidth ? "w-full" : ""}
+        // Not `disabled`: every one of these reasons is information, and
+        // `disabled` takes the button — reason and all — out of the
+        // accessibility tree. `Button` guards the click for us.
+        unavailable={unavailable}
+        unavailableReason={title}
+        onClick={onClick}
+        aria-haspopup={targets.length > 1 ? "menu" : undefined}
+        aria-expanded={targets.length > 1 ? menuOpen : undefined}
+        title={title}
+      >
+        Send to agent
+      </Button>
+      {menuOpen && targets.length > 1 && (
+        <div
+          role="menu"
+          className={`absolute right-0 z-40 min-w-[12rem] py-1 bg-[var(--bg-overlay)] border border-[var(--border-color)] rounded-[var(--radius-panel)] text-xs ${
+            dropUp ? "bottom-full mb-1" : "mt-1"
+          }`}
+          style={{ boxShadow: "var(--shadow-overlay)" }}
+        >
+          {targets.map((s) => (
+            <button
+              key={s.id}
+              type="button"
+              role="menuitem"
+              onClick={() => void send(s.id)}
+              className="w-full text-left px-3 py-1.5 text-[var(--text-primary)] hover:bg-[var(--bg-tertiary)] transition-colors"
+            >
+              {sessionDisplayName(s, project)}
+            </button>
+          ))}
+        </div>
+      )}
+    </div>
+  );
+}

app/src/components/notes/useNoteDraft.ts

@@ -0,0 +1,61 @@
+import { useEffect, useRef, useState } from "react";
+import type { Note } from "../../lib/types";
+
+/**
+ * Draft text for the note being edited, committed when a field loses focus.
+ *
+ * This is the half the dock and the tab must never disagree on, so it lives
+ * here rather than in either layout. The two surfaces differ in how they show
+ * notes; they must not differ in when a keystroke becomes a save.
+ *
+ * The draft is "untouched" exactly while it still matches what was last copied
+ * out of the store, which is what lets an edit made on the *other* surface
+ * reach this one's editor without ever discarding half-typed text.
+ */
+export function useNoteDraft(
+  selected: Note | null,
+  saveNote: (note: Note) => Promise<unknown>,
+) {
+  const [title, setTitle] = useState("");
+  const [body, setBody] = useState("");
+  const seeded = useRef<{ id: string | null; title: string; body: string }>({
+    id: null,
+    title: "",
+    body: "",
+  });
+
+  // Re-seed on a change of note, and on a change to the *stored* text of the
+  // note already open — the second case is the dock and the tab showing one
+  // project at once.
+  useEffect(() => {
+    if (!selected) {
+      seeded.current = { id: null, title: "", body: "" };
+      setTitle("");
+      setBody("");
+      return;
+    }
+    const untouched =
+      title === seeded.current.title && body === seeded.current.body;
+    if (seeded.current.id !== selected.id || untouched) {
+      seeded.current = {
+        id: selected.id,
+        title: selected.title,
+        body: selected.body,
+      };
+      setTitle(selected.title);
+      setBody(selected.body);
+    }
+  }, [selected?.id, selected?.title, selected?.body]); // eslint-disable-line react-hooks/exhaustive-deps
+
+  const commit = () => {
+    if (!selected) return;
+    // Reading is not editing: clicking through notes must not rewrite the file.
+    if (title === selected.title && body === selected.body) return;
+    // Mark the draft as matching what was just committed, so the store update
+    // this save produces reads as "no change" rather than as a stale re-seed.
+    seeded.current = { id: selected.id, title, body };
+    void saveNote({ ...selected, title, body });
+  };
+
+  return { title, body, setTitle, setBody, commit };
+}

app/src/components/projects/AddProjectDialog.test.tsx

@@ -0,0 +1,118 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { render, screen, fireEvent, waitFor, act } from "@testing-library/react";
+import AddProjectDialog from "./AddProjectDialog";
+
+const add = vi.fn();
+
+vi.mock("../../hooks/useProjects", () => ({
+  useProjects: () => ({ add }),
+}));
+
+vi.mock("@tauri-apps/plugin-dialog", () => ({
+  open: vi.fn(async () => null),
+}));
+
+/** A promise whose resolution this test controls, so `loading` can be held open. */
+function deferred() {
+  let resolve!: (v: unknown) => void;
+  const promise = new Promise((r) => {
+    resolve = r;
+  });
+  return { promise, resolve };
+}
+
+function fillValidForm() {
+  fireEvent.change(screen.getByLabelText("Project name"), {
+    target: { value: "my-project" },
+  });
+  fireEvent.change(screen.getByLabelText("Folder 1 host path"), {
+    target: { value: "/home/user/my-project" },
+  });
+}
+
+function submitButton() {
+  return screen.getByRole("button", { name: /Add Project|Adding/ });
+}
+
+describe("AddProjectDialog", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("adds the project with the name and folder entered", async () => {
+    add.mockResolvedValue({ id: "p1" });
+    const onClose = vi.fn();
+    render(<AddProjectDialog onClose={onClose} />);
+    fillValidForm();
+    fireEvent.click(submitButton());
+    await waitFor(() =>
+      expect(add).toHaveBeenCalledWith("my-project", [
+        { host_path: "/home/user/my-project", mount_name: "my-project" },
+      ]),
+    );
+    await waitFor(() => expect(onClose).toHaveBeenCalled());
+  });
+
+  it("keeps the submit button announced, and explains why, while adding", async () => {
+    const { promise, resolve } = deferred();
+    add.mockReturnValue(promise);
+    render(<AddProjectDialog onClose={vi.fn()} />);
+    fillValidForm();
+    fireEvent.click(submitButton());
+
+    // Native `disabled` would remove the button from the accessibility tree
+    // exactly when it has something to say.
+    await waitFor(() =>
+      expect(submitButton()).toHaveAttribute("aria-disabled", "true"),
+    );
+    expect(submitButton()).not.toBeDisabled();
+    expect(submitButton()).toHaveAccessibleDescription(/being added/i);
+
+    await act(async () => resolve({ id: "p1" }));
+  });
+
+  it("ignores clicks and Enter/Space on the submit button while adding", async () => {
+    const { promise, resolve } = deferred();
+    add.mockReturnValue(promise);
+    render(<AddProjectDialog onClose={vi.fn()} />);
+    fillValidForm();
+    fireEvent.click(submitButton());
+    await waitFor(() =>
+      expect(submitButton()).toHaveAttribute("aria-disabled", "true"),
+    );
+
+    fireEvent.click(submitButton());
+    fireEvent.keyDown(submitButton(), { key: "Enter" });
+    fireEvent.keyDown(submitButton(), { key: " " });
+    expect(add).toHaveBeenCalledTimes(1);
+
+    await act(async () => resolve({ id: "p1" }));
+  });
+
+  it("ignores a form submit raised from elsewhere while adding", async () => {
+    const { promise, resolve } = deferred();
+    add.mockReturnValue(promise);
+    render(<AddProjectDialog onClose={vi.fn()} />);
+    fillValidForm();
+    fireEvent.click(submitButton());
+    await waitFor(() =>
+      expect(submitButton()).toHaveAttribute("aria-disabled", "true"),
+    );
+
+    // Enter in a text field submits a form regardless of the submit button's
+    // state, so the handler has to guard itself too.
+    // Modal portals to document.body, so the form is not under `container`.
+    const form = document.querySelector("form");
+    expect(form).not.toBeNull();
+    fireEvent.submit(form!);
+    expect(add).toHaveBeenCalledTimes(1);
+
+    await act(async () => resolve({ id: "p1" }));
+  });
+
+  it("leaves the submit button plainly available when idle", () => {
+    render(<AddProjectDialog onClose={vi.fn()} />);
+    expect(submitButton()).not.toHaveAttribute("aria-disabled");
+    expect(submitButton()).toHaveAccessibleDescription("");
+  });
+});

app/src/components/projects/AddProjectDialog.tsx

@@ -55,6 +55,10 @@ export default function AddProjectDialog({ onClose }: Props) {
 
   const handleSubmit = async (e?: React.FormEvent) => {
     if (e) e.preventDefault();
+    // The submit button is `aria-disabled` rather than `disabled` while an add
+    // is in flight, and Enter inside a text field submits the form without
+    // touching the button at all. Both routes end here, so the guard does too.
+    if (loading) return;
     if (!name.trim()) {
       setError("Project name is required");
       return;
@@ -97,7 +101,19 @@ export default function AddProjectDialog({ onClose }: Props) {
           <Button size="md" variant="ghost" onClick={onClose}>
             Cancel
           </Button>
-          <Button size="md" variant="primary" type="submit" form={formId} disabled={loading}>
+          <Button
+            size="md"
+            variant="primary"
+            type="submit"
+            form={formId}
+            unavailable={loading}
+            unavailableReason="The project is being added. Wait for it to finish."
+            title={
+              loading
+                ? "The project is being added. Wait for it to finish."
+                : undefined
+            }
+          >
             {loading ? "Adding…" : "Add Project"}
           </Button>
         </>

app/src/components/projects/ClaudeCodeSettingsEditor.test.tsx

@@ -60,12 +60,18 @@ describe("ClaudeCodeSettingsEditor", () => {
   });
 
   it("offers every effort level Claude Code accepts", () => {
+    // Verified against the shipped `claude` binary's own schema rather than
+    // inferred: low/medium/high/xhigh/max. `max` was missing until an audit
+    // checked externally — which is the whole weakness of this test. It can
+    // only prove the editor agrees with this list, never that the list is the
+    // one Claude Code reads. The same blind spot is why `effort` and
+    // `focusMode` were confidently wrong for months.
     renderEditor(null);
     expect(
       Array.from(
         screen.getByLabelText("Effort level").querySelectorAll("option"),
       ).map((o) => o.getAttribute("value")),
-    ).toEqual(["", "low", "medium", "high", "xhigh"]);
+    ).toEqual(["", "low", "medium", "high", "xhigh", "max"]);
   });
 
   describe("project scope", () => {
@@ -193,4 +199,27 @@ describe("ClaudeCodeSettingsEditor", () => {
       expect(screen.getByRole("switch", { name: label })).toBeChecked();
     });
   });
+
+  /**
+   * A settings object with nothing set at this level arrives as `{}`: the Rust
+   * struct skips serialising a field it has no value for, which is what keeps
+   * an older binary able to parse `projects.json` after a downgrade. It is also
+   * the exact shape a project stored before the fields were widened is read
+   * back as — every one of its `false`s meant "unset" — so reading absent as
+   * "off" would show a switch the user never touched as a deliberate choice.
+   */
+  it("reads an absent field as Global rather than as Off", () => {
+    renderEditor({} as ClaudeCodeSettings, "project");
+    expect((screen.getByLabelText("Env scrub") as HTMLSelectElement).value).toBe("global");
+    expect((screen.getByLabelText("Session recap") as HTMLSelectElement).value).toBe("global");
+  });
+
+  it("still collapses to null when an absent-field object is edited back", () => {
+    const onSave = renderEditor({} as ClaudeCodeSettings, "global");
+    // Off and straight back on: the round trip has to land on `null`, or an
+    // untouched global stops being indistinguishable from one never opened.
+    fireEvent.click(screen.getByRole("switch", { name: "Session recap" }));
+    fireEvent.click(screen.getByRole("switch", { name: "Session recap" }));
+    expect(onSave).toHaveBeenLastCalledWith(null);
+  });
 });

app/src/components/projects/ClaudeCodeSettingsEditor.tsx

@@ -37,15 +37,20 @@ export const CLAUDE_CODE_DEFAULTS: ClaudeCodeSettings = {
  * overrides a global on, so a settings object holding one has to be persisted.
  */
 function isAllDefaults(s: ClaudeCodeSettings): boolean {
+  // `== null`, not `===`: an unset field is *absent* on the wire, not null.
+  // The Rust struct skips serialising one it has no value for, so a project
+  // whose stored settings were all "unset" arrives here as `{}` — and reading
+  // that as "off" is exactly the mistake the three-state control exists to
+  // avoid. See the note on `ClaudeCodeSettings` in `lib/types.ts`.
   return (
-    s.tui_mode === null &&
-    s.effort === null &&
-    s.auto_scroll_disabled === null &&
-    s.focus_mode === null &&
-    s.show_thinking_summaries === null &&
-    s.session_recap_disabled === null &&
-    s.env_scrub === null &&
-    s.prompt_caching_1h === null
+    s.tui_mode == null &&
+    s.effort == null &&
+    s.auto_scroll_disabled == null &&
+    s.focus_mode == null &&
+    s.show_thinking_summaries == null &&
+    s.session_recap_disabled == null &&
+    s.env_scrub == null &&
+    s.prompt_caching_1h == null
   );
 }
 
@@ -63,7 +68,15 @@ const BOOLEAN_FIELDS: {
   hint: string;
   invert?: boolean;
 }[] = [
-  { key: "focus_mode", label: "Focus mode", hint: "Collapses tool output to one-line summaries." },
+  {
+    key: "focus_mode",
+    label: "Focus mode",
+    // It summarises tool *calls*, not all output — and it does nothing at all
+    // unless the fullscreen renderer is on, which is a separate switch above.
+    // Saying so here is cheaper than the user concluding the setting is broken,
+    // which is the complaint that started this whole round of work.
+    hint: "Summarises each tool call to one line, showing the last prompt and the final response. Needs TUI mode set to Fullscreen.",
+  },
   {
     key: "show_thinking_summaries",
     label: "Thinking summaries",
@@ -163,6 +176,9 @@ export default function ClaudeCodeSettingsEditor({
             <option value="medium">Medium</option>
             <option value="high">High</option>
             <option value="xhigh">Extra high</option>
+            {/* `max` is accepted by the CLI and was missing here. Confirmed
+                against the shipped claude binary's own schema, not just docs. */}
+            <option value="max">Maximum</option>
           </select>
         }
       />
@@ -204,7 +220,7 @@ export default function ClaudeCodeSettingsEditor({
         // `stored` holds the deviation from Claude Code's default, so an
         // inverted field reads back the other way round — see BOOLEAN_FIELDS.
         const selected =
-          stored === null ? "global" : (invert ? !stored : stored) ? "on" : "off";
+          stored == null ? "global" : (invert ? !stored : stored) ? "on" : "off";
 
         return (
           <SwitchRow

app/src/components/projects/ProjectRow.test.tsx

@@ -122,14 +122,6 @@ describe("ProjectRow", () => {
   });
 
   it("only allows opening a terminal while the container runs", () => {
-    const { unmount } = render(<ProjectRow project={baseProject} />);
-    expect(
-      screen.getByRole("button", {
-        name: "Open a Claude terminal for Test Project",
-      }),
-    ).toBeDisabled();
-    unmount();
-
     render(<ProjectRow project={{ ...baseProject, status: "running" }} />);
     fireEvent.click(
       screen.getByRole("button", {
@@ -139,6 +131,38 @@ describe("ProjectRow", () => {
     expect(mockOpenClaudeTerminal).toHaveBeenCalled();
   });
 
+  it("keeps the terminal button announced, and explains why, while stopped", () => {
+    render(<ProjectRow project={baseProject} />);
+    const button = screen.getByRole("button", {
+      name: "Open a Claude terminal for Test Project",
+    });
+    // Native `disabled` would drop the button out of the accessibility tree
+    // and out of the tab order, taking the reason with it.
+    expect(button).not.toBeDisabled();
+    expect(button).toHaveAttribute("aria-disabled", "true");
+    expect(button).toHaveAccessibleDescription(/is not running/i);
+  });
+
+  it("ignores clicks and Enter/Space on the terminal button while stopped", () => {
+    render(<ProjectRow project={baseProject} />);
+    const button = screen.getByRole("button", {
+      name: "Open a Claude terminal for Test Project",
+    });
+    fireEvent.click(button);
+    fireEvent.keyDown(button, { key: "Enter" });
+    fireEvent.keyDown(button, { key: " " });
+    expect(mockOpenClaudeTerminal).not.toHaveBeenCalled();
+  });
+
+  it("drops aria-disabled once the container is running", () => {
+    render(<ProjectRow project={{ ...baseProject, status: "running" }} />);
+    const button = screen.getByRole("button", {
+      name: "Open a Claude terminal for Test Project",
+    });
+    expect(button).not.toHaveAttribute("aria-disabled");
+    expect(button).not.toHaveAccessibleDescription(/is not running/i);
+  });
+
   it("shows container progress inline rather than in a blocking modal", () => {
     setStore({ containerProgress: { "test-1": "Pulling image…" } });
     render(<ProjectRow project={{ ...baseProject, status: "starting" }} />);

app/src/components/projects/ProjectRow.tsx

@@ -3,6 +3,7 @@ import type { Project } from "../../lib/types";
 import { useAppState, homeTabKey } from "../../store/appState";
 import { useProjectActions } from "../../hooks/useProjectActions";
 import { ProjectStatusIndicator } from "../ui/StatusIndicator";
+import { useUnavailable } from "../ui/unavailable";
 
 interface Props {
   project: Project;
@@ -31,6 +32,15 @@ export default function ProjectRow({ project }: Props) {
   const isTransitioning =
     project.status === "starting" || project.status === "stopping";
 
+  // A terminal needs a running container. Saying so out loud beats a `disabled`
+  // attribute that hides the button — and the reason — from anyone not using a
+  // mouse and eyes.
+  const terminal = useUnavailable({
+    unavailable: !isRunning,
+    reason: `${project.name} is not running. Start it to open a terminal.`,
+    onClick: () => openClaudeTerminal(),
+  });
+
   return (
     <div
       className={`group relative px-2 py-1.5 rounded-[var(--radius-control)] transition-colors min-w-0 overflow-hidden ${
@@ -113,11 +123,14 @@ export default function ProjectRow({ project }: Props) {
         </button>
         <button
           type="button"
-          disabled={!isRunning}
-          onClick={() => openClaudeTerminal()}
-          title={`Open a Claude terminal for ${project.name}`}
+          {...terminal.controlProps}
+          title={
+            isRunning
+              ? `Open a Claude terminal for ${project.name}`
+              : `${project.name} is not running. Start it to open a terminal.`
+          }
           aria-label={`Open a Claude terminal for ${project.name}`}
-          className="w-6 h-6 flex items-center justify-center rounded-[var(--radius-control)] text-[var(--text-secondary)] hover:text-[var(--text-primary)] hover:bg-[var(--bg-primary)] disabled:text-[var(--text-disabled)] transition-colors"
+          className="w-6 h-6 flex items-center justify-center rounded-[var(--radius-control)] text-[var(--text-secondary)] hover:text-[var(--text-primary)] hover:bg-[var(--bg-primary)] disabled:text-[var(--text-disabled)] aria-disabled:text-[var(--text-disabled)] aria-disabled:hover:text-[var(--text-disabled)] aria-disabled:hover:bg-transparent aria-disabled:cursor-not-allowed transition-colors"
         >
           <svg
             className="w-3.5 h-3.5"
@@ -134,6 +147,7 @@ export default function ProjectRow({ project }: Props) {
             <line x1="13" y1="15" x2="17" y2="15" />
           </svg>
         </button>
+        {terminal.reasonNode}
       </div>
     </div>
   );

app/src/components/projects/home/BrowserTab.tsx

@@ -23,6 +23,7 @@ import {
   setBrowserViewMatchWindow,
   setBrowserViewPopoutAlwaysOnTop,
 } from "../../../lib/tauri-commands";
+import { isBrowserViewUsable } from "../../../lib/browserViewSupport";
 import { useAppState } from "../../../store/appState";
 import OpenPageDialog from "./OpenPageDialog";
 import AccordionSection from "../../ui/AccordionSection";
@@ -338,7 +339,7 @@ export default function BrowserTab({ project, active }: Props) {
   // Prefer the probe: it is the fresher of the two, and it is the one that
   // reflects an install that just finished.
   const probed = detection ?? status.detection;
-  const ready = isUsable(probed);
+  const ready = isBrowserViewUsable(probed);
   // Mirrors Rust `PlaywrightDetection::needs_browser`: the Chrome channel is an
   // apt package, so it never shows up in `browsers`, and a container that has
   // it is not missing a browser.
@@ -539,11 +540,6 @@ export default function BrowserTab({ project, active }: Props) {
   );
 }
 
-/** Mirrors Rust `PlaywrightDetection::is_usable`. */
-function isUsable(d: PlaywrightDetection | null): boolean {
-  return d !== null && d.playwright_version !== null && d.has_bind && d.cli_entry !== null;
-}
-
 /**
  * Mirrors Rust `PlaywrightDetection::revision_skew`.
  *
@@ -627,7 +623,7 @@ function Setup({
   onInstall: (which: Exclude<SetupJob, null>) => void;
 }) {
   const busy = job !== null;
-  const havePackages = isUsable(detection);
+  const havePackages = isBrowserViewUsable(detection);
   const missing = missingParts(detection);
   const browsers = detection?.browsers ?? [];
   const chrome = detection?.chrome_channel ?? null;

app/src/components/projects/home/FileViewerModal.tsx

@@ -16,14 +16,12 @@ interface Props {
   projectId: string;
   entry: FileEntry;
   onClose: () => void;
-  /** "Save to host…" — the way out for anything the viewer can't render. */
-  onSaveToHost: (entry: FileEntry) => void;
 }
 
 type Preview =
   | { kind: "loading" }
   | { kind: "error"; message: string }
-  /** Too big to render whole — offered as a download rather than a half-file. */
+  /** Too big to render whole — said so rather than shown as a half-file. */
   | { kind: "too-large" }
   | { kind: "text"; text: string; truncated: boolean; shownBytes: number; trueSize: number }
   | { kind: "image"; url: string }
@@ -37,7 +35,7 @@ type Preview =
  * keeps a multi-megabyte base64 string out of the DOM. `blob:` is in the app's
  * `img-src` for exactly this; the asset protocol deliberately is not enabled.
  */
-export default function FileViewerModal({ projectId, entry, onClose, onSaveToHost }: Props) {
+export default function FileViewerModal({ projectId, entry, onClose }: Props) {
   const [preview, setPreview] = useState<Preview>({ kind: "loading" });
 
   /**
@@ -121,19 +119,9 @@ export default function FileViewerModal({ projectId, entry, onClose, onSaveToHos
   );
 
   const footer = (
-    <>
-      <Button
-        size="md"
-        onClick={() => {
-          onSaveToHost(entry);
-        }}
-      >
-        Save to host…
-      </Button>
-      <Button size="md" variant="primary" onClick={onClose}>
-        Close
-      </Button>
-    </>
+    <Button size="md" variant="primary" onClick={onClose}>
+      Close
+    </Button>
   );
 
   return (
@@ -156,14 +144,16 @@ export default function FileViewerModal({ projectId, entry, onClose, onSaveToHos
 
       {preview.kind === "too-large" && (
         <p className="text-[13px] text-[var(--text-secondary)]">
-          This file is {formatBytes(entry.size)} — too large to preview in the app. Save it
-          to the host to open it there.
+          This file is {formatBytes(entry.size)} — too large to preview in the app. Use
+          “Save to host…” on its row to open it in a program that can, or read it from a
+          terminal in the container.
         </p>
       )}
 
       {preview.kind === "unsupported" && (
         <p className="text-[13px] text-[var(--text-secondary)]">
-          There is no preview for this file type. Save it to the host to open it there.
+          There is no preview for this file type. Use “Save to host…” on its row to open it
+          in a program that can, or read it from a terminal in the container.
         </p>
       )}
 

app/src/components/projects/home/FilesTab.test.tsx

@@ -1,23 +1,23 @@
 import { describe, it, expect, vi, beforeEach } from "vitest";
-import { render, screen, fireEvent, act, waitFor } from "@testing-library/react";
+import { render, screen, fireEvent, act, waitFor, within } from "@testing-library/react";
 import FilesTab from "./FilesTab";
 import type { FileContents, FileEntry, Project } from "../../../lib/types";
 
 const listContainerFiles = vi.fn();
-const downloadContainerFile = vi.fn(async () => {});
-const uploadFileToContainer = vi.fn(async () => {});
 const renameContainerPath = vi.fn(async () => "");
 const createContainerDirectory = vi.fn(async () => "");
 const readContainerFile = vi.fn();
+const uploadFilesToContainer = vi.fn();
+const downloadContainerFile = vi.fn();
 
 vi.mock("../../../lib/tauri-commands", () => ({
   listContainerFiles: (p: string, path: string) => listContainerFiles(p, path),
-  downloadContainerFile: (p: string, c: string, h: string) => downloadContainerFile(p, c, h),
-  uploadFileToContainer: (...args: unknown[]) => uploadFileToContainer(...args),
   renameContainerPath: (p: string, f: string, t: string) => renameContainerPath(p, f, t),
   createContainerDirectory: (p: string, parent: string, n: string) =>
     createContainerDirectory(p, parent, n),
   readContainerFile: (p: string, path: string, max?: number) => readContainerFile(p, path, max),
+  uploadFilesToContainer: (p: string, dir: string) => uploadFilesToContainer(p, dir),
+  downloadContainerFile: (p: string, path: string) => downloadContainerFile(p, path),
 }));
 
 /** Transient failures land in `ToastHost`, not in an inline string. */
@@ -31,29 +31,6 @@ const toastText = () =>
     .map(([toast]) => `${toast.kind}: ${toast.message} ${toast.detail ?? ""}`)
     .join("\n");
 
-const save = vi.fn(async () => "/host/out");
-vi.mock("@tauri-apps/plugin-dialog", () => ({
-  save: (o: unknown) => save(o),
-  open: vi.fn(async () => null),
-}));
-
-/** The webview's window-wide native drag-drop listener, captured for driving. */
-type DragPayload =
-  | { type: "enter" | "over"; position: { x: number; y: number }; paths: string[] }
-  | { type: "leave" }
-  | { type: "drop"; position: { x: number; y: number }; paths: string[] };
-let dragHandler: ((e: { payload: DragPayload }) => void | Promise<void>) | null = null;
-const unlistenDrag = vi.fn();
-
-vi.mock("@tauri-apps/api/webview", () => ({
-  getCurrentWebview: () => ({
-    onDragDropEvent: async (cb: (e: { payload: DragPayload }) => void) => {
-      dragHandler = cb;
-      return unlistenDrag;
-    },
-  }),
-}));
-
 const project = { id: "p1", name: "api", status: "running" } as unknown as Project;
 
 const entry = (name: string, extra: Partial<FileEntry> = {}): FileEntry => ({
@@ -82,39 +59,17 @@ async function renderTab() {
   return view;
 }
 
-/** Fire the native drop payload at a point inside the pane's stubbed rect. */
-async function drop(paths: string[], position = { x: 100, y: 100 }) {
-  await act(async () => {
-    await dragHandler?.({ payload: { type: "drop", position, paths } });
-  });
-}
-
 /** Every row that is part of the grid's roving tabindex, in order. */
 const gridRows = () => Array.from(document.querySelectorAll("tr[data-file-row]"));
 /** The rows that are actually tab stops. There must never be more than one. */
 const tabStops = () => gridRows().filter((r) => r.getAttribute("tabindex") === "0");
 
-/** Fire a drop without awaiting it — for the paths that stop to ask a question. */
-function dropWithoutWaiting(paths: string[], position = { x: 100, y: 100 }) {
-  let pending: unknown;
-  act(() => {
-    pending = dragHandler?.({ payload: { type: "drop", position, paths } });
-  });
-  return pending as Promise<void> | undefined;
-}
-
 beforeEach(() => {
   vi.clearAllMocks();
-  dragHandler = null;
   listContainerFiles.mockResolvedValue([
     entry("src", { is_directory: true, path: "/workspace/src" }),
     entry("notes.txt"),
   ]);
-  // jsdom lays nothing out, so the pane's hit-test rect has to be supplied.
-  vi.spyOn(HTMLElement.prototype, "getBoundingClientRect").mockReturnValue({
-    x: 0, y: 0, left: 0, top: 0, right: 800, bottom: 600, width: 800, height: 600,
-    toJSON: () => ({}),
-  } as DOMRect);
   // Not implemented in jsdom; the image preview needs both halves.
   URL.createObjectURL = vi.fn(() => "blob:mock-url");
   URL.revokeObjectURL = vi.fn();
@@ -224,7 +179,15 @@ describe("FilesTab viewer", () => {
     });
     expect(await screen.findByText(/too large to preview/)).toBeTruthy();
     expect(screen.queryByAltText("huge.png")).toBeNull();
-    expect(screen.getByRole("button", { name: "Save to host…" })).toBeTruthy();
+    // A refusal has to name the way out, and the way out is now the button on
+    // the row rather than the `cat`-it-in-a-terminal workaround that existed
+    // because the button did not.
+    // Scoped to the modal: every file row also carries a "Save to host…"
+    // button now, so an unscoped query matches the grid behind the overlay and
+    // would pass with the refusal saying nothing at all.
+    expect(
+      within(screen.getByRole("dialog")).getByText(/Save to host/),
+    ).toBeTruthy();
   });
 
   it("says so in words when only a prefix of a big text file came back", async () => {
@@ -239,7 +202,7 @@ describe("FilesTab viewer", () => {
     expect(screen.getByText("first megabyte")).toBeTruthy();
   });
 
-  it("offers Save to host for a file it cannot render", async () => {
+  it("says there is no preview, and where to open the file instead", async () => {
     listContainerFiles.mockResolvedValue([entry("blob.bin")]);
     readContainerFile.mockResolvedValue(contents("a\x00b"));
     await renderTab();
@@ -314,191 +277,6 @@ describe("FilesTab new folder", () => {
   });
 });
 
-describe("FilesTab host drag-and-drop", () => {
-  it("uploads dropped paths into the directory on screen, then re-lists", async () => {
-    await renderTab();
-    listContainerFiles.mockClear();
-    await drop(["/host/a.png", "/host/b.png"]);
-    expect(uploadFileToContainer).toHaveBeenNthCalledWith(1, "p1", "/host/a.png", "/workspace");
-    expect(uploadFileToContainer).toHaveBeenNthCalledWith(2, "p1", "/host/b.png", "/workspace");
-    expect(listContainerFiles).toHaveBeenCalledWith("p1", "/workspace");
-  });
-
-  it("drops into the directory the user has navigated to", async () => {
-    await renderTab();
-    await act(async () => {
-      fireEvent.doubleClick(screen.getByText("src"));
-    });
-    await drop(["/host/a.png"]);
-    expect(uploadFileToContainer).toHaveBeenCalledWith("p1", "/host/a.png", "/workspace/src");
-  });
-
-  it("ignores a drop outside the pane — the listener is window-wide", async () => {
-    // This is the whole routing discipline: the terminal's listener is live at
-    // the same time, and only the hit-test keeps them apart.
-    await renderTab();
-    await drop(["/host/a.png"], { x: 5000, y: 5000 });
-    expect(uploadFileToContainer).not.toHaveBeenCalled();
-  });
-
-  it("divides the payload position by devicePixelRatio on Windows only", async () => {
-    // Only wry's WebView2 backend hands over *physical* pixels; the macOS and
-    // GTK ones deliver logical points and `tauri-runtime-wry` does not rescale
-    // them. At dpr 2 a physical (900, 900) is a CSS (450, 450) — inside the
-    // 800x600 pane — but the same payload on a HiDPI Mac or Linux box really
-    // is (900, 900) and belongs to nobody.
-    const originalDpr = window.devicePixelRatio;
-    const originalUa = window.navigator.userAgent;
-    Object.defineProperty(window, "devicePixelRatio", { value: 2, configurable: true });
-    Object.defineProperty(window.navigator, "userAgent", {
-      value: "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36",
-      configurable: true,
-    });
-    await renderTab();
-    await drop(["/host/a.png"], { x: 900, y: 900 });
-    expect(uploadFileToContainer).toHaveBeenCalled();
-
-    Object.defineProperty(window.navigator, "userAgent", {
-      value: "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15",
-      configurable: true,
-    });
-    vi.mocked(uploadFileToContainer).mockClear();
-    await drop(["/host/a.png"], { x: 900, y: 900 });
-    expect(uploadFileToContainer).not.toHaveBeenCalled();
-    // …and the *unhalved* point still lands, which is the half a HiDPI Mac
-    // user was losing.
-    await drop(["/host/a.png"], { x: 400, y: 300 });
-    expect(uploadFileToContainer).toHaveBeenCalled();
-
-    Object.defineProperty(window, "devicePixelRatio", {
-      value: originalDpr,
-      configurable: true,
-    });
-    Object.defineProperty(window.navigator, "userAgent", {
-      value: originalUa,
-      configurable: true,
-    });
-  });
-
-  it("accepts a drop that lands on a toast floating over the pane", async () => {
-    // Round 1. `ToastHost` is `fixed bottom-4 right-4 z-[60]` and 24rem wide,
-    // and its error cards stay until dismissed — so a z-order gate asking "is
-    // what is painted here part of my pane?" made the bottom-right corner of
-    // this pane refuse drops for as long as one error was on screen. jsdom has
-    // no `elementFromPoint`, so that branch only ran when a test supplied one;
-    // the gate no longer asks, and this pins that nothing painted over a pane
-    // can refuse a drop on its own account.
-    await renderTab();
-    const toastCard = document.createElement("div");
-    document.body.appendChild(toastCard);
-    Object.defineProperty(document, "elementFromPoint", {
-      configurable: true,
-      writable: true,
-      value: () => toastCard,
-    });
-
-    await drop(["/host/a.png"], { x: 700, y: 550 });
-    expect(uploadFileToContainer).toHaveBeenCalled();
-
-    delete (document as Partial<Document>).elementFromPoint;
-    toastCard.remove();
-  });
-
-  it("refuses a drop while a dialog is open, toast painted over it or not", async () => {
-    // Round 2, which is the reason this file exists in its current shape. The
-    // refusal pushes a toast; `ToastHost` is `z-[60]` and the `Modal` backdrop
-    // is `z-50` in the same stacking context, so the *toast* becomes the
-    // topmost element over a covered pane. A gate that asked `elementFromPoint`
-    // "is a blocker painted here?" then answered no and uploaded into the
-    // directory the dialog was covering — one refused drop was all it took to
-    // open the hole. Both stubs below therefore have to be refused.
-    await renderTab();
-    const backdrop = document.createElement("div");
-    backdrop.setAttribute("data-blocks-drop", "true");
-    document.body.appendChild(backdrop);
-    const toastCard = document.createElement("div"); // z-[60], above the backdrop
-    document.body.appendChild(toastCard);
-    const stub = (top: Element) =>
-      Object.defineProperty(document, "elementFromPoint", {
-        configurable: true,
-        writable: true,
-        value: () => top,
-      });
-
-    stub(backdrop);
-    await drop(["/host/a.png"], { x: 400, y: 300 });
-    expect(uploadFileToContainer).not.toHaveBeenCalled();
-
-    stub(toastCard);
-    await drop(["/host/a.png"], { x: 700, y: 550 });
-    expect(uploadFileToContainer).not.toHaveBeenCalled();
-
-    delete (document as Partial<Document>).elementFromPoint;
-    toastCard.remove();
-    backdrop.remove();
-  });
-
-  it("highlights the pane while a drag hovers it, and drops the highlight on leave", async () => {
-    await renderTab();
-    await act(async () => {
-      await dragHandler?.({
-        payload: { type: "over", position: { x: 100, y: 100 }, paths: [] },
-      });
-    });
-    expect(screen.getByText(/Drop files into \/workspace/)).toBeTruthy();
-    await act(async () => {
-      await dragHandler?.({ payload: { type: "leave" } });
-    });
-    expect(screen.queryByText(/Drop files into/)).toBeNull();
-  });
-});
-
-describe("FilesTab save to host", () => {
-  it("copies a file out to the path the user picks", async () => {
-    await renderTab();
-    await act(async () => {
-      fireEvent.click(screen.getByRole("button", { name: "Save to host… — notes.txt" }));
-    });
-    expect(downloadContainerFile).toHaveBeenCalledWith("p1", "/workspace/notes.txt", "/host/out");
-  });
-
-  it("does not offer a directory download, which cannot work", async () => {
-    await renderTab();
-    expect(screen.queryByRole("button", { name: "Save to host… — src" })).toBeNull();
-  });
-});
-
-describe("FilesTab drop hit test", () => {
-  it("uploads nothing when a dialog is covering the pane", async () => {
-    // The pane still has its rect underneath the viewer's `fixed inset-0`
-    // portal, which is exactly why a rect alone was the wrong test.
-    readContainerFile.mockResolvedValue(contents("hello"));
-    await renderTab();
-    await act(async () => {
-      fireEvent.doubleClick(screen.getByText("notes.txt"));
-    });
-    await screen.findByRole("dialog");
-
-    await drop(["/host/a.png"]);
-
-    expect(uploadFileToContainer).not.toHaveBeenCalled();
-  });
-
-  it("does not paint the hint under a dialog either", async () => {
-    readContainerFile.mockResolvedValue(contents("hello"));
-    await renderTab();
-    await act(async () => {
-      fireEvent.doubleClick(screen.getByText("notes.txt"));
-    });
-    await screen.findByRole("dialog");
-
-    await act(async () => {
-      await dragHandler?.({ payload: { type: "over", position: { x: 100, y: 100 }, paths: [] } });
-    });
-    expect(screen.queryByText(/Drop files into/)).toBeNull();
-  });
-});
-
 describe("FilesTab grid focus", () => {
   it("gives the grid exactly one tab stop and moves it with the arrows", async () => {
     // Every row used to be `tabIndex={0}`: a 400-entry directory was ~1200 tab
@@ -592,22 +370,28 @@ describe("FilesTab grid semantics", () => {
     await renderTab();
     const rename = screen.getByRole("button", { name: "Rename — notes.txt" });
     expect(rename.textContent).toBe("Rename");
-    expect(rename.getAttribute("aria-label")).toContain("Rename");
-    const saveTo = screen.getByRole("button", { name: "Save to host… — notes.txt" });
-    expect(saveTo.getAttribute("aria-label")).toContain(saveTo.textContent!);
+    expect(rename.getAttribute("aria-label")).toContain(rename.textContent!);
   });
 
   it("mounts the live region empty, then fills it", async () => {
     // A `role="status"` node inserted already carrying its text is frequently
     // not announced at all, which is how every one of these went by in silence.
+    createContainerDirectory.mockResolvedValue("/workspace/new");
     await renderTab();
     const live = screen.getByRole("status");
     expect(live.textContent).toBe("");
 
-    await drop(["/host/a.png"]);
+    await act(async () => {
+      fireEvent.click(screen.getByRole("button", { name: "New folder" }));
+    });
+    const input = screen.getByLabelText("New folder name");
+    fireEvent.change(input, { target: { value: "new" } });
+    await act(async () => {
+      fireEvent.blur(input);
+    });
     // Same node throughout — it is never unmounted.
     expect(screen.getByRole("status")).toBe(live);
-    expect(live.textContent).toContain("Uploaded 1 item");
+    expect(live.textContent).toContain('Created "new"');
   });
 
   it("keeps a listing failure inline, where the rows it explains are missing", async () => {
@@ -619,129 +403,72 @@ describe("FilesTab grid semantics", () => {
   });
 });
 
-describe("FilesTab overwrite prompt", () => {
-  it("asks before replacing, and re-uploads with overwrite on Replace", async () => {
-    uploadFileToContainer.mockRejectedValueOnce("FILE_EXISTS: /workspace/notes.txt already exists");
-    await renderTab();
-
-    const pending = dropWithoutWaiting(["/host/notes.txt"]);
-    const dialog = await screen.findByRole("dialog");
-    expect(dialog.textContent).toContain("notes.txt");
-
-    await act(async () => {
-      fireEvent.click(screen.getByRole("button", { name: "Replace" }));
-      await pending;
-    });
-
-    expect(uploadFileToContainer).toHaveBeenLastCalledWith(
-      "p1",
-      "/host/notes.txt",
-      "/workspace",
-      true,
-    );
-    expect(screen.queryByRole("dialog")).toBeNull();
-  });
-
-  it("uploads nothing more on Skip", async () => {
-    uploadFileToContainer.mockRejectedValueOnce("FILE_EXISTS: /workspace/notes.txt already exists");
-    await renderTab();
-
-    const pending = dropWithoutWaiting(["/host/notes.txt"]);
-    await screen.findByRole("dialog");
-    await act(async () => {
-      fireEvent.click(screen.getByRole("button", { name: "Skip" }));
-      await pending;
-    });
-
-    expect(uploadFileToContainer).toHaveBeenCalledTimes(1);
-    expect(screen.queryByRole("dialog")).toBeNull();
-  });
-
-  it("offers the blanket answers only when files are queued behind this one", async () => {
-    uploadFileToContainer.mockRejectedValueOnce("FILE_EXISTS: /workspace/a.txt already exists");
-    await renderTab();
-
-    const pending = dropWithoutWaiting(["/host/a.txt", "/host/b.txt"]);
-    await screen.findByRole("dialog");
-    expect(screen.getByRole("button", { name: "Replace all" })).toBeTruthy();
-
-    await act(async () => {
-      fireEvent.click(screen.getByRole("button", { name: "Skip all" }));
-      await pending;
-    });
-    expect(screen.queryByRole("dialog")).toBeNull();
-  });
-});
-
 /**
- * Dismissal. `Modal` gives every dialog Escape, a ✕ and click-outside for free,
- * and `OverwriteConfirmModal` maps all three onto `onChoose("skip")` — because
- * the destructive answer has to be chosen, and because a dialog that is closed
- * rather than answered must not leave the batch waiting forever or throw away
- * the files behind it.
+ * The pane's two host-transfer affordances.
+ *
+ * They are asserted at the *button* level and not only in the hook, because
+ * this is the half that was actually lost: the commands behind them had been
+ * deleted, but so had the controls, and a working command nobody can reach is
+ * the same regression. Neither button names a host path — Rust opens the
+ * dialog — so what a click is required to prove is that the container-side
+ * argument reaching the backend is the one the user is looking at.
  */
-describe("FilesTab overwrite prompt dismissal", () => {
-  /**
-   * Drop two files where the first name is taken, and stop at the dialog. The
-   * unsettled batch comes back wrapped — returning it bare from an `async`
-   * helper would adopt it, and awaiting the helper would then wait for an
-   * upload that cannot proceed until the helper has returned.
-   */
-  async function dropIntoConflict(): Promise<{ batch: Promise<void> | undefined }> {
-    uploadFileToContainer.mockRejectedValueOnce("FILE_EXISTS: /workspace/a.txt already exists");
+describe("FilesTab host transfers", () => {
+  beforeEach(() => {
+    uploadFilesToContainer.mockResolvedValue({ uploaded: [], failures: [] });
+    downloadContainerFile.mockResolvedValue(4);
+  });
+
+  it("uploads into the directory currently on screen", async () => {
+    listContainerFiles.mockResolvedValue([entry("src", { is_directory: true })]);
     await renderTab();
-    const batch = dropWithoutWaiting(["/host/a.txt", "/host/b.txt"]);
-    await screen.findByRole("dialog");
-    return { batch };
-  }
-
-  /** What every dismissal has to leave behind: one skip, one upload, no clobber. */
-  function expectSkippedAndCarriedOn() {
-    expect(screen.queryByRole("dialog")).toBeNull();
-    expect(uploadFileToContainer).toHaveBeenCalledTimes(2);
-    expect(uploadFileToContainer).toHaveBeenLastCalledWith("p1", "/host/b.txt", "/workspace");
-    expect(uploadFileToContainer.mock.calls.some((call) => call[3] === true)).toBe(false);
-    expect(screen.getByRole("status").textContent).toContain("skipped 1");
-  }
-
-  it("counts Escape as a Skip", async () => {
-    const { batch } = await dropIntoConflict();
     await act(async () => {
-      fireEvent.keyDown(document, { key: "Escape" });
-      await batch;
+      fireEvent.doubleClick(screen.getByText("src"));
     });
-    expectSkippedAndCarriedOn();
+    uploadFilesToContainer.mockResolvedValueOnce({
+      uploaded: ["/workspace/src/a.txt"],
+      failures: [],
+    });
+    await act(async () => {
+      fireEvent.click(screen.getByRole("button", { name: "Upload…" }));
+    });
+    expect(uploadFilesToContainer).toHaveBeenCalledWith("p1", "/workspace/src");
   });
 
-  it("counts the ✕ as a Skip", async () => {
-    const { batch } = await dropIntoConflict();
+  it("offers Save to host on a file and not on a folder", async () => {
+    listContainerFiles.mockResolvedValue([
+      entry("notes.txt"),
+      entry("src", { is_directory: true }),
+    ]);
+    await renderTab();
+    // The accessible name carries the row, per WCAG 2.5.3 — and it is how a
+    // per-row action is told apart from every other row's copy of it.
+    expect(
+      screen.getByRole("button", { name: "Save to host — notes.txt" }),
+    ).toBeTruthy();
+    expect(
+      screen.queryByRole("button", { name: "Save to host — src" }),
+    ).toBeNull();
     await act(async () => {
-      fireEvent.click(screen.getByRole("button", { name: "Close dialog" }));
-      await batch;
+      fireEvent.click(screen.getByRole("button", { name: "Save to host — notes.txt" }));
     });
-    expectSkippedAndCarriedOn();
+    expect(downloadContainerFile).toHaveBeenCalledWith("p1", "/workspace/notes.txt");
   });
 
-  it("counts a click on the backdrop as a Skip", async () => {
-    const { batch } = await dropIntoConflict();
-    // The overlay is the dialog panel's parent — `Modal` only closes when the
-    // click landed on the overlay itself, not on anything inside the panel.
-    const overlay = screen.getByRole("dialog").parentElement!;
+  it("does not open the file viewer when Save to host is double-clicked", async () => {
+    // Opening a file is a *double*-click on the row, and a double-click on a
+    // button inside that row still bubbles — `onClick`'s `stopPropagation` does
+    // nothing about it. So an impatient double-click on Save used to save the
+    // file and drop the viewer modal over the pane at the same time, on top of
+    // the save dialog the backend had just opened.
+    listContainerFiles.mockResolvedValue([entry("notes.txt")]);
+    readContainerFile.mockResolvedValue(contents("hello"));
+    await renderTab();
     await act(async () => {
-      fireEvent.click(overlay);
-      await batch;
+      fireEvent.doubleClick(
+        screen.getByRole("button", { name: "Save to host — notes.txt" }),
+      );
     });
-    expectSkippedAndCarriedOn();
-  });
-
-  it("does not dismiss on a click inside the dialog", async () => {
-    const { batch } = await dropIntoConflict();
-    fireEvent.click(screen.getByRole("dialog"));
-    expect(screen.queryByRole("dialog")).not.toBeNull();
-    await act(async () => {
-      fireEvent.click(screen.getByRole("button", { name: "Replace" }));
-      await batch;
-    });
-    expect(uploadFileToContainer).toHaveBeenNthCalledWith(2, "p1", "/host/a.txt", "/workspace", true);
+    expect(readContainerFile).not.toHaveBeenCalled();
   });
 });

app/src/components/projects/home/FilesTab.tsx

@@ -1,12 +1,8 @@
 import { useCallback, useEffect, useMemo, useRef, useState } from "react";
-import { getCurrentWebview } from "@tauri-apps/api/webview";
 import type { FileEntry, Project } from "../../../lib/types";
 import { useFileManager } from "../../../hooks/useFileManager";
-import { classifyDrop, isDropTarget, DROP_BLOCKED_TOAST } from "../../../lib/dropTarget";
-import { useAppState } from "../../../store/appState";
 import Button from "../../ui/Button";
 import FileViewerModal from "./FileViewerModal";
-import OverwriteConfirmModal from "./OverwriteConfirmModal";
 import { formatBytes } from "./format";
 
 interface Props {
@@ -17,7 +13,28 @@ interface Props {
 const PARENT_ROW = "..";
 
 /**
- * The project's file manager.
+ * The project's file browser.
+ *
+ * It lists, opens, renames and creates folders inside the container, and it
+ * copies single files across the boundary: "Upload…" in the toolbar, and a
+ * per-row "Save to host…".
+ *
+ * **Neither of those names a host path, and this file must never learn how
+ * to.** Four successive audits found that host paths crossing IPC were where
+ * the criticals lived — a frontend `open()`/`save()` handing Rust a string is
+ * exactly the shape that failed — so the picker is opened by the *backend*
+ * (`pick_files_to_upload` / `pick_save_path` in `commands/file_commands.rs`).
+ * What this file *sends* is a project id and a container path; the host side of
+ * the transfer is chosen by a person in an OS dialog. That is why
+ * `uploadFiles()` takes no argument and `saveToHost()` takes only the entry.
+ * (A failed transfer does report a host path back, in the text of its error —
+ * the inbound direction is the one that is closed, not both.)
+ *
+ * Drag-and-drop is deliberately still absent, in both directions. A file also
+ * gets into a container by being dropped onto the Terminal tab, and a whole
+ * tree comes back out through "Back up container" in the project's ⋯ menu —
+ * which is still the right answer for a directory, since "Save to host…" is one
+ * file at a time and is not offered on folders.
  *
  * Interaction model, chosen to match every desktop file manager rather than
  * the old half-and-half: **single click selects, double click opens**. That
@@ -42,18 +59,16 @@ export default function FilesTab({ project }: Props) {
     entries,
     loading,
     error,
-    busy,
     completed,
-    conflict,
-    resolveConflict,
     navigate,
     goUp,
     refresh,
-    downloadFile,
-    uploadFile,
-    uploadPaths,
     renameEntry,
     createFolder,
+    uploadFiles,
+    saveToHost,
+    uploading,
+    savingPaths,
   } = useFileManager(project.id);
 
   const running = project.status === "running";
@@ -65,8 +80,6 @@ export default function FilesTab({ project }: Props) {
   const [creatingFolder, setCreatingFolder] = useState(false);
   const [folderDraft, setFolderDraft] = useState("");
   const [viewing, setViewing] = useState<FileEntry | null>(null);
-  /** A host drag is currently over this pane. */
-  const [dragOver, setDragOver] = useState(false);
   /** The row that owns the grid's single tab stop. */
   const [activeRow, setActiveRow] = useState<string | null>(null);
 
@@ -234,58 +247,6 @@ export default function FilesTab({ project }: Props) {
     goUp();
   }, [currentPath, goUp]);
 
-  // Host → container drag and drop.
-  //
-  // This is Tauri's *native* drag-drop event, not HTML5 `ondrop`, for the same
-  // reason `TerminalView` uses it: `dragDropEnabled` is on (the terminal needs
-  // it), which blocks HTML5 drag inside the webview on Windows, and only the
-  // native payload carries real file *paths*. The listener is window-wide, so
-  // routing is `classifyDrop` — the rect hit test, which says *whose* drop it
-  // is, plus the document-wide question a rect cannot answer: is a modal or a
-  // blocking overlay on screen at all? That second half is deliberately not a
-  // per-point z-order test; `lib/dropTarget.ts` records the two ways that went
-  // wrong.
-  useEffect(() => {
-    if (!running) return;
-    let unlisten: (() => void) | undefined;
-    let cancelled = false;
-
-    (async () => {
-      const un = await getCurrentWebview().onDragDropEvent(async (event) => {
-        const payload = event.payload;
-        if (payload.type === "leave") {
-          setDragOver(false);
-          return;
-        }
-        if (payload.type === "enter" || payload.type === "over") {
-          setDragOver(isDropTarget(paneRef.current, payload.position));
-          return;
-        }
-        if (payload.type !== "drop") return;
-        setDragOver(false);
-        const verdict = classifyDrop(paneRef.current, payload.position);
-        // Aimed at this pane and refused anyway: say so. Nothing else would —
-        // the file just never appears in the listing.
-        if (verdict === "blocked") {
-          console.warn("[drop] refused: a dialog or overlay is open", payload.position);
-          useAppState.getState().pushToast(DROP_BLOCKED_TOAST);
-          return;
-        }
-        if (verdict !== "accept") return;
-        const paths = payload.paths ?? [];
-        if (paths.length === 0) return;
-        await uploadPaths(paths);
-      });
-      if (cancelled) un();
-      else unlisten = un;
-    })();
-
-    return () => {
-      cancelled = true;
-      unlisten?.();
-    };
-  }, [running, uploadPaths]);
-
   const breadcrumbs =
     currentPath === "/"
       ? [{ label: "/", path: "/" }]
@@ -324,10 +285,10 @@ export default function FilesTab({ project }: Props) {
   /**
    * The live region's text. One region, always mounted, filled and emptied —
    * a `role="status"` node that is *inserted* already carrying its text is
-   * frequently not announced at all, which is how "uploading 3 items…" and
-   * every completion notice used to go by in silence.
+   * frequently not announced at all, which is how every completion notice used
+   * to go by in silence.
    */
-  const liveText = busy ? busy : (completed ?? "");
+  const liveText = completed ?? "";
 
   return (
     <div ref={paneRef} className="relative flex flex-col h-full min-h-0">
@@ -361,8 +322,15 @@ export default function FilesTab({ project }: Props) {
         >
           New folder
         </Button>
-        <Button onClick={uploadFile} className="ml-1">
-          Upload file
+        {/* The file picker this opens belongs to Rust, not to the webview — so
+            this file imports no dialog plugin and never composes a host path.
+            `uploadFiles` takes no argument for the same reason. */}
+        <Button
+          onClick={() => void uploadFiles()}
+          disabled={uploading}
+          className="ml-1"
+        >
+          {uploading ? "Uploading…" : "Upload…"}
         </Button>
         <Button onClick={refresh} disabled={loading} className="ml-1">
           Refresh
@@ -372,9 +340,9 @@ export default function FilesTab({ project }: Props) {
       <div className="flex-1 overflow-y-auto min-h-0">
         {/* The one failure that stays inline: it explains why the grid below is
             empty, it is in context, and there are no rows for it to scroll
-            behind. Every *transient* failure — upload, rename, mkdir,
-            save-to-host — goes to `ToastHost` instead, which is above
-            the file viewer's overlay and does not scroll away. */}
+            behind. Every *transient* failure — rename, new folder — goes to
+            `ToastHost` instead, which is above the file viewer's overlay and
+            does not scroll away. */}
         {error && (
           <div role="alert" className="px-4 py-2 text-xs text-[var(--error)]">
             {error}
@@ -560,16 +528,32 @@ export default function FilesTab({ project }: Props) {
                           >
                             Rename
                           </Button>
+                          {/* Folders have no single-file equivalent — a
+                              recursive download is what "Back up container" is
+                              for, and offering one here would mean rebuilding
+                              the tree-walking this pane deliberately does not
+                              do. */}
                           {!entry.is_directory && (
                             <Button
-                              aria-label={`Save to host… — ${entry.name}`}
+                              aria-label={`Save to host — ${entry.name}`}
                               className="ml-1"
+                              // Only this row: a large file can take a while,
+                              // and there is no reason the rest of the pane
+                              // should go dead while it is written.
+                              disabled={savingPaths.has(entry.path)}
                               onClick={(e) => {
                                 e.stopPropagation();
-                                downloadFile(entry);
+                                void saveToHost(entry);
                               }}
+                              // A double-click is its own event, and
+                              // `onClick`'s `stopPropagation` says nothing
+                              // about it — so an impatient double-click here
+                              // reached the row's `onDoubleClick` and dropped
+                              // the viewer modal over the pane, on top of the
+                              // save dialog the backend had just opened.
+                              onDoubleClick={(e) => e.stopPropagation()}
                             >
-                              Save to host…
+                              {savingPaths.has(entry.path) ? "Saving…" : "Save to host…"}
                             </Button>
                           )}
                         </>
@@ -594,34 +578,11 @@ export default function FilesTab({ project }: Props) {
         )}
       </div>
 
-      {/* Drop hint. Purely decorative — the native listener is what accepts the
-          drop, so this must never intercept pointer events. */}
-      {dragOver && (
-        <div
-          aria-hidden="true"
-          className="pointer-events-none absolute inset-0 flex items-center justify-center border-2 border-dashed border-[var(--accent)] bg-[var(--bg-primary)]/70"
-        >
-          <span className="text-[13px] font-medium text-[var(--text-primary)]">
-            Drop files into {currentPath}
-          </span>
-        </div>
-      )}
-
-      {conflict && (
-        <OverwriteConfirmModal
-          name={conflict.name}
-          directory={conflict.directory}
-          remaining={conflict.remaining}
-          onChoose={resolveConflict}
-        />
-      )}
-
       {viewing && (
         <FileViewerModal
           projectId={project.id}
           entry={viewing}
           onClose={() => setViewing(null)}
-          onSaveToHost={downloadFile}
         />
       )}
     </div>

app/src/components/projects/home/NotesTab.tsx

@@ -0,0 +1,20 @@
+import type { Project } from "../../../lib/types";
+import NotesPanel from "../../notes/NotesPanel";
+
+interface Props {
+  project: Project;
+}
+
+/**
+ * Notes as a Project Home sub-tab.
+ *
+ * The same panel the dock shows. This is the roomy view for writing; the dock
+ * is the one that stays visible while the agent works.
+ */
+export default function NotesTab({ project }: Props) {
+  return (
+    <div className="h-full min-h-0">
+      <NotesPanel projectId={project.id} />
+    </div>
+  );
+}

app/src/components/projects/home/OverwriteConfirmModal.tsx

@@ -1,73 +0,0 @@
-import type { OverwriteChoice } from "../../../lib/uploadErrors";
-import Button from "../../ui/Button";
-import Modal from "../../ui/Modal";
-
-interface Props {
-  /** Bare name of the file that is already there. */
-  name: string;
-  /** Container directory it is going into. */
-  directory: string;
-  /** How many more files are queued behind this one. */
-  remaining: number;
-  onChoose: (choice: OverwriteChoice) => void;
-}
-
-/**
- * "That name is taken — replace it?"
- *
- * This exists because the backend stopped overwriting silently, and a raw
- * error string would have been a worse answer than the old silent clobber: it
- * tells the user their drop failed without telling them it *can* succeed. The
- * dialog names the file and the directory, because a drop is aimed with a
- * mouse and "notes.txt" alone does not say which `notes.txt`.
- *
- * The blanket answers only appear when there is something to apply them to — a
- * single-file drop with "Replace all" on it invites the reflex of clicking the
- * widest button for no benefit.
- *
- * Dismissing (Escape, ✕, click-outside) is a **skip**, never a replace: the
- * destructive answer has to be chosen explicitly.
- */
-export default function OverwriteConfirmModal({ name, directory, remaining, onChoose }: Props) {
-  const footer = (
-    <>
-      {remaining > 0 && (
-        <>
-          <Button size="md" onClick={() => onChoose("skip-all")}>
-            Skip all
-          </Button>
-          <Button size="md" onClick={() => onChoose("replace-all")}>
-            Replace all
-          </Button>
-        </>
-      )}
-      <Button size="md" onClick={() => onChoose("skip")}>
-        Skip
-      </Button>
-      <Button size="md" variant="primary" onClick={() => onChoose("replace")}>
-        Replace
-      </Button>
-    </>
-  );
-
-  return (
-    <Modal
-      title="A file with that name is already there"
-      description={directory}
-      onClose={() => onChoose("skip")}
-      footer={footer}
-      widthClassName="w-[30rem]"
-    >
-      <p className="text-[13px] text-[var(--text-primary)]">
-        <span className="font-mono">{name}</span> already exists in{" "}
-        <span className="font-mono">{directory}</span>. Replacing it overwrites the container's
-        copy, and that cannot be undone from here.
-      </p>
-      {remaining > 0 && (
-        <p className="mt-2 text-xs text-[var(--text-secondary)]">
-          {remaining} more file{remaining === 1 ? "" : "s"} still to upload.
-        </p>
-      )}
-    </Modal>
-  );
-}

app/src/components/projects/home/ProjectHome.tsx

@@ -1,5 +1,6 @@
 import { useEffect, useMemo, useState } from "react";
 import { useShallow } from "zustand/react/shallow";
+import { projectRemovalIsClean } from "../../../lib/types";
 import { useAppState } from "../../../store/appState";
 import { useProjectActions } from "../../../hooks/useProjectActions";
 import { useProjects } from "../../../hooks/useProjects";
@@ -17,7 +18,9 @@ import AutomationTab from "./AutomationTab";
 import ConfigTab from "./ConfigTab";
 import FilesTab from "./FilesTab";
 import BrowserTab from "./BrowserTab";
+import NotesTab from "./NotesTab";
 import { formatUptime } from "./format";
+import { describeLeftovers, leftoverPronoun, leftoverVerb } from "./removalReport";
 
 const TABS = [
   { id: "overview", label: "Overview" },
@@ -26,6 +29,7 @@ const TABS = [
   { id: "config", label: "Config" },
   { id: "files", label: "Files" },
   { id: "browser", label: "Browser" },
+  { id: "notes", label: "Notes" },
 ] as const;
 
 export type ProjectHomeTabId = (typeof TABS)[number]["id"];
@@ -253,6 +257,7 @@ export default function ProjectHome({ projectId, active }: Props) {
         {tab === "browser" && (
           <BrowserTab project={project} active={active && tab === "browser"} />
         )}
+        {tab === "notes" && <NotesTab project={project} />}
       </div>
 
       {showMigration && (
@@ -282,7 +287,25 @@ export default function ProjectHome({ projectId, active }: Props) {
           onConfirm={async () => {
             setConfirmRemove(false);
             try {
-              await remove(project.id);
+              const report = await remove(project.id);
+              if (!projectRemovalIsClean(report)) {
+                const verb = leftoverVerb(report);
+                if (report.retry_scheduled) {
+                  useAppState.getState().pushToast({
+                    kind: "info",
+                    message: `“${project.name}” was removed, but Triple-C could not confirm all its Docker resources were removed`,
+                    detail: `Triple-C could not confirm ${describeLeftovers(report)} ${verb} removed. It will check again the next time it starts.`,
+                  });
+                } else {
+                  // The pending-cleanup record itself failed to save — no
+                  // retry will happen, so this must not promise one.
+                  useAppState.getState().pushToast({
+                    kind: "error",
+                    message: `“${project.name}” was removed, but Triple-C could not confirm its Docker resources were removed`,
+                    detail: `Triple-C could not confirm ${describeLeftovers(report)} ${verb} removed, and could not record this for a retry. You may need to remove ${leftoverPronoun(report)} manually (\`docker rm\` / \`docker rmi\` / \`docker volume rm\`).`,
+                  });
+                }
+              }
             } catch (e) {
               useAppState.getState().pushToast({
                 kind: "error",

app/src/components/projects/home/config/RuntimeSection.tsx

@@ -109,7 +109,16 @@ export default function RuntimeSection({
 
       <ConfigGroup
         title="Claude Code settings"
-        description="Per-project CLI behaviour. Anything left on Global follows Settings; Off overrides a global On."
+        description={
+          "Per-project CLI behaviour. Anything left on Global follows Settings; " +
+          "Off overrides a global On. Changing any of these recreates the container, " +
+          "which commits a new image layer — so flipping switches repeatedly costs disk. " +
+          "Turning TUI mode, Effort level, Focus mode or Session recap back to Global " +
+          "also needs the base image updated first: those four are cleared by removing a " +
+          "key, and an older image's startup script ignores the instruction to remove it. " +
+          "Update the base image from Overview. TUI mode, Effort level and Focus mode " +
+          "visibly refuse to switch off until you do; Session recap just stays off silently."
+        }
       >
         <ClaudeCodeSettingsEditor
           scope="project"

app/src/components/projects/home/config/WorkspaceSection.test.tsx

@@ -0,0 +1,177 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { render, screen, fireEvent, act } from "@testing-library/react";
+import WorkspaceSection from "./WorkspaceSection";
+import type { Project } from "../../../../lib/types";
+
+// The Browse button is the OS folder picker.
+const open = vi.fn();
+vi.mock("@tauri-apps/plugin-dialog", () => ({
+  open: (...args: unknown[]) => open(...args),
+}));
+
+const baseProject: Project = {
+  id: "p1",
+  name: "api-server",
+  paths: [{ host_path: "/src/api", mount_name: "api" }],
+  container_id: null,
+  status: "stopped",
+  backend: "anthropic",
+  bedrock_config: null,
+  ollama_config: null,
+  llamacpp_config: null,
+  openai_compatible_config: null,
+  allow_docker_access: false,
+  sandbox_mode_enabled: true,
+  mission_control_enabled: false,
+  auth_bridge_enabled: false,
+  browser_view_enabled: false,
+  vpn_support_enabled: false,
+  use_shared_auth_token: true,
+  full_permissions: false,
+  permission_mode: null,
+  ssh_key_path: null,
+  ca_cert_path: null,
+  git_token: null,
+  git_user_name: null,
+  git_user_email: null,
+  custom_env_vars: [],
+  port_mappings: [],
+  claude_instructions: null,
+  claude_code_settings: null,
+  renamed_session_names: {},
+  created_at: "2026-01-01T00:00:00Z",
+  updated_at: "2026-01-01T00:00:00Z",
+};
+
+const save = vi.fn().mockResolvedValue(true);
+
+function renderSection(over: Partial<Project> = {}, disabled = false) {
+  return render(
+    <WorkspaceSection
+      project={{ ...baseProject, ...over }}
+      save={save}
+      disabled={disabled}
+    />,
+  );
+}
+
+/** Every folder list this component has sent to `update_project`. */
+function savedLists() {
+  return save.mock.calls
+    .filter(([patch]) => "paths" in patch)
+    .map(([patch]) => patch.paths);
+}
+
+describe("WorkspaceSection — the blank row is never stored", () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  /**
+   * The bug this file exists for. `create_container` mounts every stored row
+   * unfiltered, so a persisted `{host_path: "", mount_name: ""}` becomes
+   * `{"Target": "/workspace/", "Source": ""}` and the daemon refuses the whole
+   * container with `field Source must not be empty` — the project can never be
+   * started or recreated again. Click "+ Add folder", blur a field, and it is
+   * bricked.
+   */
+  it("drops the placeholder row when a real edit is saved", () => {
+    renderSection();
+    fireEvent.click(screen.getByRole("button", { name: "+ Add folder" }));
+
+    const hostPath = screen.getByLabelText("Folder 1 host path");
+    fireEvent.change(hostPath, { target: { value: "/src/api-v2" } });
+    fireEvent.blur(hostPath);
+
+    expect(save).toHaveBeenCalledTimes(1);
+    expect(savedLists()[0]).toEqual([{ host_path: "/src/api-v2", mount_name: "api" }]);
+  });
+
+  it("drops it when Browse fills a different row in", async () => {
+    open.mockResolvedValueOnce("/src/api-v2");
+    renderSection();
+    fireEvent.click(screen.getByRole("button", { name: "+ Add folder" }));
+
+    // The picker is awaited inside the handler, so the state update that
+    // follows it lands outside the click.
+    await act(async () => {
+      fireEvent.click(screen.getAllByRole("button", { name: "Browse" })[0]);
+    });
+
+    expect(savedLists()[0]).toEqual([{ host_path: "/src/api-v2", mount_name: "api" }]);
+  });
+
+  it("drops it when a row is removed", () => {
+    renderSection({
+      paths: [
+        { host_path: "/src/api", mount_name: "api" },
+        { host_path: "/src/web", mount_name: "web" },
+      ],
+    });
+    fireEvent.click(screen.getByRole("button", { name: "+ Add folder" }));
+    fireEvent.click(screen.getByRole("button", { name: "Remove folder 2" }));
+
+    expect(savedLists()[0]).toEqual([{ host_path: "/src/api", mount_name: "api" }]);
+  });
+
+  it("never sends a row with an empty host path, whatever the route", () => {
+    renderSection();
+    fireEvent.click(screen.getByRole("button", { name: "+ Add folder" }));
+    const hostPath = screen.getByLabelText("Folder 1 host path");
+    fireEvent.change(hostPath, { target: { value: "/src/api-v2" } });
+    fireEvent.blur(hostPath);
+
+    for (const list of savedLists()) {
+      for (const row of list) {
+        expect(row.host_path).not.toBe("");
+        expect(row.mount_name).not.toBe("");
+      }
+    }
+  });
+});
+
+describe("WorkspaceSection — what a blur is allowed to save", () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  /**
+   * Both inputs save on blur, so tabbing from the host path to the mount name
+   * fires a save with the name still empty — which `update_project` refuses,
+   * turning an ordinary keystroke into an error toast.
+   */
+  it("holds a half-filled row back until it is complete", () => {
+    renderSection();
+    fireEvent.click(screen.getByRole("button", { name: "+ Add folder" }));
+
+    const newHostPath = screen.getByLabelText("Folder 2 host path");
+    fireEvent.change(newHostPath, { target: { value: "/src/web" } });
+    fireEvent.blur(newHostPath);
+    expect(save).not.toHaveBeenCalled();
+
+    const newMountName = screen.getByLabelText("Folder 2 mount name");
+    fireEvent.change(newMountName, { target: { value: "web" } });
+    fireEvent.blur(newMountName);
+    expect(savedLists()[0]).toEqual([
+      { host_path: "/src/api", mount_name: "api" },
+      { host_path: "/src/web", mount_name: "web" },
+    ]);
+  });
+
+  /**
+   * Blurring out of an untouched field is not an edit. Saving anyway would
+   * round-trip the filtered list through `project` and take the empty row away
+   * while the user was still filling it in.
+   */
+  it("saves nothing when the blur changed nothing", () => {
+    renderSection();
+    fireEvent.click(screen.getByRole("button", { name: "+ Add folder" }));
+    fireEvent.blur(screen.getByLabelText("Folder 1 mount name"));
+    expect(save).not.toHaveBeenCalled();
+    expect(screen.getByLabelText("Folder 2 host path")).toBeTruthy();
+  });
+
+  it("still saves a rename, which does not go through the folder list", () => {
+    renderSection();
+    const name = screen.getByDisplayValue("api-server");
+    fireEvent.change(name, { target: { value: "api-v2" } });
+    fireEvent.blur(name);
+    expect(save).toHaveBeenCalledWith({ name: "api-v2" });
+  });
+});

app/src/components/projects/home/config/WorkspaceSection.tsx

@@ -10,6 +10,14 @@ interface Props {
   disabled: boolean;
 }
 
+/** Whether two folder lists are the same rows in the same order. */
+function sameRows(a: ProjectPath[], b: ProjectPath[]): boolean {
+  return (
+    a.length === b.length &&
+    a.every((row, i) => row.host_path === b[i].host_path && row.mount_name === b[i].mount_name)
+  );
+}
+
 export default function WorkspaceSection({ project, save, disabled }: Props) {
   const [name, setName] = useState(project.name);
   const [paths, setPaths] = useState<ProjectPath[]>(project.paths ?? []);
@@ -19,6 +27,27 @@ export default function WorkspaceSection({ project, save, disabled }: Props) {
     setPaths(project.paths ?? []);
   }, [project]);
 
+  /**
+   * Persist a folder list, minus the rows that are only in it because the UI
+   * put them there.
+   *
+   * **The blank row must never reach the store.** "+ Add folder" inserts
+   * `{host_path: "", mount_name: ""}` deliberately, and `create_container`
+   * mounts every stored row unfiltered — a stored blank one becomes
+   * `{"Target": "/workspace/", "Source": ""}`, which the daemon rejects with
+   * `field Source must not be empty`. The project then cannot be started or
+   * recreated at all, from a click and a blur. `AddProjectDialog` has always
+   * filtered this; this section computed the filtered list and then saved the
+   * unfiltered one.
+   *
+   * Every save goes through here for that reason — Browse and Remove write the
+   * list too, and either can be holding a blank row from an earlier click.
+   */
+  const persist = (rows: ProjectPath[]) => {
+    const filled = rows.filter((p) => p.host_path.trim() || p.mount_name.trim());
+    return save({ paths: filled });
+  };
+
   /**
    * Save only when every row is fully filled in.
    *
@@ -27,12 +56,18 @@ export default function WorkspaceSection({ project, save, disabled }: Props) {
    * a half-filled row is refused — so the unconditional save turned an ordinary
    * keystroke into an error toast. A blank row is *not* incomplete: the
    * "+ Add folder" button adds one deliberately, and it is dropped on save.
+   *
+   * A blur that changed nothing saves nothing, which is what keeps the blank
+   * row on screen while it is being filled in: persisting the filtered list
+   * would round-trip through `project` and take the empty row away under the
+   * cursor.
    */
   const saveIfComplete = () => {
     const filled = paths.filter((p) => p.host_path.trim() || p.mount_name.trim());
     const halfFilled = filled.some((p) => !p.host_path.trim() || !p.mount_name.trim());
     if (halfFilled) return;
-    return save({ paths });
+    if (sameRows(filled, project.paths ?? [])) return;
+    return persist(paths);
   };
 
   return (
@@ -106,7 +141,7 @@ export default function WorkspaceSection({ project, save, disabled }: Props) {
                         mount_name: updated[i].mount_name || basename,
                       };
                       setPaths(updated);
-                      save({ paths: updated });
+                      persist(updated);
                     }
                   }}
                 >
@@ -137,7 +172,7 @@ export default function WorkspaceSection({ project, save, disabled }: Props) {
                     onClick={() => {
                       const updated = paths.filter((_, j) => j !== i);
                       setPaths(updated);
-                      save({ paths: updated });
+                      persist(updated);
                     }}
                   >
                     Remove

app/src/components/projects/home/filePreview.test.ts

@@ -3,6 +3,7 @@ import {
   IMAGE_PREVIEW_LIMIT,
   TEXT_PREVIEW_LIMIT,
   decodeBase64,
+  encodeBase64,
   extensionOf,
   imageMimeFor,
   looksBinary,
@@ -76,3 +77,22 @@ describe("decodeBase64 / looksBinary", () => {
     expect(looksBinary(bytes)).toBe(false);
   });
 });
+
+describe("encodeBase64", () => {
+  it("matches btoa on a small input", () => {
+    expect(encodeBase64(new Uint8Array([0xff, 0xd8, 0x00, 0x41]))).toBe(btoa("\xff\xd8\x00\x41"));
+  });
+
+  it("round-trips 1 MiB without overflowing the call stack", () => {
+    // Spreading a 1 MiB array into String.fromCharCode throws RangeError in V8.
+    const bytes = new Uint8Array(TEXT_PREVIEW_LIMIT);
+    for (let i = 0; i < bytes.length; i++) bytes[i] = (i * 31 + 7) & 0xff;
+    const back = decodeBase64(encodeBase64(bytes));
+    expect(back.length).toBe(bytes.length);
+    expect(back.every((b, i) => b === bytes[i])).toBe(true);
+  });
+
+  it("encodes an empty input as the empty string", () => {
+    expect(encodeBase64(new Uint8Array(0))).toBe("");
+  });
+});

app/src/components/projects/home/filePreview.ts

@@ -96,6 +96,19 @@ export function decodeBase64(base64: string): Uint8Array<ArrayBuffer> {
   return bytes;
 }
 
+/**
+ * Bytes → base64. Built 32 KiB at a time: spreading a whole buffer into
+ * `String.fromCharCode` overflows the argument limit well below 1 MiB.
+ */
+export function encodeBase64(bytes: Uint8Array): string {
+  const CHUNK = 0x8000;
+  let binary = "";
+  for (let i = 0; i < bytes.length; i += CHUNK) {
+    binary += String.fromCharCode(...bytes.subarray(i, i + CHUNK));
+  }
+  return btoa(binary);
+}
+
 /**
  * The classic heuristic: a NUL byte early on means this is not text. Cheap,
  * and it is what `git` and `grep` use to decide the same question.

app/src/components/projects/home/removalReport.test.ts

@@ -0,0 +1,51 @@
+import { describe, it, expect } from "vitest";
+import { describeLeftovers, leftoverVerb } from "./removalReport";
+import { projectRemovalIsClean } from "../../../lib/types";
+import type { ProjectRemovalReport } from "../../../lib/types";
+
+function report(overrides: Partial<ProjectRemovalReport> = {}): ProjectRemovalReport {
+  return {
+    container: null,
+    image: null,
+    volumes: [],
+    retry_scheduled: false,
+    ...overrides,
+  };
+}
+
+describe("projectRemovalIsClean", () => {
+  it("is true only when nothing survived", () => {
+    expect(projectRemovalIsClean(report())).toBe(true);
+    expect(projectRemovalIsClean(report({ container: "triple-c-abc" }))).toBe(false);
+    expect(projectRemovalIsClean(report({ image: "triple-c-snapshot-abc:latest" }))).toBe(false);
+    expect(projectRemovalIsClean(report({ volumes: ["triple-c-home-abc"] }))).toBe(false);
+  });
+});
+
+describe("describeLeftovers", () => {
+  it("names each kind of leftover", () => {
+    expect(describeLeftovers(report({ container: "triple-c-abc" }))).toBe("its container");
+    expect(describeLeftovers(report({ image: "x" }))).toBe("its saved image");
+    expect(describeLeftovers(report({ volumes: ["v1"] }))).toBe("a volume");
+    expect(describeLeftovers(report({ volumes: ["v1", "v2"] }))).toBe("2 volumes");
+  });
+
+  it("joins multiple kinds together", () => {
+    expect(
+      describeLeftovers(report({ container: "triple-c-abc", image: "x", volumes: ["v1", "v2"] })),
+    ).toBe("its container, its saved image, 2 volumes");
+  });
+});
+
+describe("leftoverVerb", () => {
+  it("is singular for exactly one leftover of any kind", () => {
+    expect(leftoverVerb(report({ container: "triple-c-abc" }))).toBe("was");
+    expect(leftoverVerb(report({ image: "x" }))).toBe("was");
+    expect(leftoverVerb(report({ volumes: ["v1"] }))).toBe("was");
+  });
+
+  it("is plural once more than one thing survived, including multiple volumes alone", () => {
+    expect(leftoverVerb(report({ container: "triple-c-abc", image: "x" }))).toBe("were");
+    expect(leftoverVerb(report({ volumes: ["v1", "v2"] }))).toBe("were");
+  });
+});