Add a Disk section: see where the bytes went, and get them back

Every recreation runs `docker commit`, which stacks a layer and never
rewrites one, and 24 conditions in `container_needs_recreation` trigger a
recreation. Prevention landed earlier on this branch; this is the half a
user can act on.

The per-project table leads with the two numbers that explain the
mechanism rather than just the total: how many commit layers a snapshot
has stacked above its base, and what the container's writable layer will
add at the next commit.

Backend (`docker/disk.rs`, commands in `docker_commands.rs`):
- `get_docker_disk_usage` — one `df()` joined against the project store,
  behind an explicit Scan button because it walks the whole daemon.
- `list_reclaimable` / `reclaim` — classified buckets with measured bytes,
  planned off the existing report so re-planning costs no second scan.
- `destroy_project_disk_object` — one object, typed confirmation.
- `sweep_orphaned_snapshots` — exposed, so its report is finally visible.

Safety is structural: `reclaim` takes `ReclaimTarget`, which has no
variant that can name a live project's data. Destructive work is a
separate type reached only through `destroy`. No unfiltered prune is
called anywhere, and nothing outside a `triple-c*` name or `triple-c.*`
label is touched.

Orphan detection subtracts ids from the project store and consults
nothing else. From the daemon's side an idle live project and a deleted
one are indistinguishable — volumes present, no container, no image — so
inferring from container or image absence would offer a live project's
credentials and transcripts for deletion. A store that loaded empty from
an existing `projects.json` is treated as a failed load, not as "no
projects", because `ProjectsStore::new()` recovers from a corrupt file by
starting empty.

Three things verified against a live Docker 29.7.2 rather than assumed:

- Compaction is a two-stage build (`FROM scratch` + `COPY --from`), which
  keeps every byte inside the daemon; bollard's import buffers a whole
  image into memory. uid/gid and setuid survive; a 192.6 MB/4-layer
  synthetic came out 45.7 MB/1 layer. Image config does not survive, so it
  is replayed via create+commit, which round-trips a multi-line env var
  that a Dockerfile `ENV` could not.
- Flattening breaks base-layer sharing, so the result carries its own copy
  of the base. Eight of ten real projects had a 0.10–1.32 GB delta over a
  4.72 GB shared base — compacting those costs ~4 GB. The bound now
  subtracts that penalty, such projects are not offered at all, and the
  run compares unique bytes and abandons a rewrite that would grow.
- `docker builder prune` reports `Total:`, not `Total reclaimed space:`,
  so the first parser scored every prune as freeing nothing.

The Windows/WSL2 note is mandatory and its copy lives in Rust beside the
tests that pin it: pruning frees space inside `ext4.vhdx`, which never
shrinks on its own, so C: does not change until the disk is compacted.

Also adds `lib/formatBytes.ts` — the app had four disagreeing copies, and
`projects/home/format.ts` and `migrationCopy.ts` now delegate to it with
byte-identical output. Base 1000 by default, matching what Docker prints.

Tests: 502 frontend (was 453), 365 Rust (was 322).

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GBq2rGum6GX7xXgsas1fDc

app/src/lib/tauri-commands.ts

@@ -1,5 +1,5 @@
 import { invoke } from "@tauri-apps/api/core";
-import type { Project, ProjectPath, ContainerInfo, SiblingContainer, AppSettings, UpdateInfo, ImageUpdateInfo, FileEntry, FileContents, WebTerminalInfo, SttStatus, GatewayStatus, InstallOptions, ClaudeSession, ContainerCapabilities, ScheduledTask, ScheduledTaskInput, SchedulerNotification, AuthBridgeStatus, BrowserViewStatus, BrowserViewPopoutState, BrowserPageState, PlaywrightDetection, BrowserSetupOutcome, BrowserInstallTarget, ContainerStaleness, MigrationOptions, MigrationReport, MigrationState, ClearTokenOutcome, CaCertInfo } from "./types";
+import type { Project, ProjectPath, ContainerInfo, SiblingContainer, AppSettings, UpdateInfo, ImageUpdateInfo, FileEntry, FileContents, WebTerminalInfo, SttStatus, GatewayStatus, InstallOptions, ClaudeSession, ContainerCapabilities, ScheduledTask, ScheduledTaskInput, SchedulerNotification, AuthBridgeStatus, BrowserViewStatus, BrowserViewPopoutState, BrowserPageState, PlaywrightDetection, BrowserSetupOutcome, BrowserInstallTarget, ContainerStaleness, MigrationOptions, MigrationReport, MigrationState, ClearTokenOutcome, CaCertInfo, DiskUsageReport, ReclaimPlan, ReclaimTarget, ReclaimOutcome, ReclaimResult, DestructiveTarget, SnapshotSweepReport } from "./types";
 
 // Docker
 export const checkDocker = () => invoke<boolean>("check_docker");
@@ -349,3 +349,34 @@ export const rollbackMigration = (projectId: string) =>
  *  app crash shows up here as phase "interrupted". */
 export const getMigrationState = (projectId: string) =>
   invoke<MigrationState | null>("get_migration_state", { projectId });
+
+// Disk
+
+/** Measure where the daemon's bytes have gone.
+ *
+ *  **Expensive — keep it behind an explicit Scan button.** This is
+ *  `GET /system/df`, which walks every image, container and volume on the
+ *  daemon to compute shared-layer sizes, plus an `image_history` per image.
+ *  Seconds on a 100 GB store. Never call it on mount and never poll it. */
+export const getDockerDiskUsage = () => invoke<DiskUsageReport>("get_docker_disk_usage");
+
+/** Classify what could be reclaimed, with measured bytes. Takes the report
+ *  from `getDockerDiskUsage` so re-planning costs no second scan. */
+export const listReclaimable = (report: DiskUsageReport) =>
+  invoke<ReclaimPlan>("list_reclaimable", { report });
+
+/** Run the ticked targets. `ReclaimTarget` cannot name a destructive action,
+ *  so no selection built here can delete a live project's data. */
+export const reclaim = (targets: ReclaimTarget[]) =>
+  invoke<ReclaimOutcome>("reclaim", { targets });
+
+/** Delete one object that has no other copy. `confirmation` must be the
+ *  project's name, typed by the user. One target per call, never bulk. */
+export const destroyProjectDiskObject = (target: DestructiveTarget, confirmation: string) =>
+  invoke<ReclaimResult>("destroy_project_disk_object", { target, confirmation });
+
+/** Run the orphaned-snapshot sweep on demand and see its report — the same
+ *  sweep that runs at startup and after every recreation, whose result every
+ *  existing caller throws away. */
+export const sweepOrphanedSnapshots = () =>
+  invoke<SnapshotSweepReport>("sweep_orphaned_snapshots");