Fix review findings: secrets in snapshots, URL spoofing, migration data loss

Adversarial review of the branch produced findings across four areas.
This addresses them, plus the Windows CI environment.

Secrets. commit_container_snapshot baked the container's full env into
the per-project snapshot image, so the shared OAuth token — and the AWS
keys, git token and gateway master key — outlived revocation and were
readable via docker inspect. Verified against Engine 29.6 that a commit
body's config merges over the container's: keys cannot be dropped but
can be overwritten, so all of them now commit as KEY=. clear_claude_token
additionally rewrites images from earlier builds and reports honestly
when a tag could not be rewritten.

The recommendation to move the token out of env entirely was not taken,
with reasoning: apiKeyHelper is a different auth method that outranks
CLAUDE_CODE_OAUTH_TOKEN rather than a transport for it, and no
file-based delivery exists. The durable exposure — the image — is what
is closed here. Separately noted, not fixed: entrypoint.sh captures the
token into the scheduler's .env inside the persisted volume.

URL spoofing. Three call sites reached openUrl with container-controlled
strings, one of which the review missed (the WebLinksAddon handler).
The sign-in URL was scraped from container output with a longest-match
tie-break and no userinfo check, so claude.ai@evil.tld rendered as
"claude.ai…" in a truncating element. There is now one sanitizer in
front of every sink — scheme allowlist, no userinfo, C0/C1 and quote
rejection, host allowlist for the sign-in case, first-match — and the
origin renders un-truncated. The toast is keyed so a changed URL
remounts, closing a bait-and-switch where the user read one URL and
clicked another.

Migration. The rollback pin was best-effort: a tag failure was logged
and the migration continued past remove_container, after which the
final commit overwrote the only copy of the old system layer. It now
aborts before anything destructive and reads the tag back. /var was
destroyed while the ordinary recreate path preserves it — making the
"safe" alternative to Reset more destructive than Reset's alternative;
data-bearing subtrees are now detected and disclosed in the pre-flight
rather than copied, since tarring a live database onto a different
base's packages is a corruption risk. resume_migration now verifies the
migration-state label instead of reporting success for a container that
never swapped. dismiss actually resolves the record rather than leaving
the feature permanently refusing to migrate. Start and Reset are guarded
while a migration is live.

Lifecycle. The gateway no longer publishes on 0.0.0.0 — bind address and
advertised URL are derived together so they cannot drift. Disabling it
now stops it. App exit runs teardown concurrently under a budget with a
visible shutting-down state instead of blocking for minutes. Auto-starts
retry when Docker is not up yet, and the polling-recovery path now
reconciles, so interrupted migrations are still recovered. Auth-bridge
forwards are capped, closing a container-driven fd exhaustion.

Windows CI. build-windows failed on this branch with "linker link.exe
not found". The runner had no MSVC build tools and the workflow assumed
a hand-provisioned machine, so a bare runner registers, accepts jobs and
fails at link time after downloading the whole crate graph. The job now
installs the VC++ workload when vswhere cannot find it, matching how it
already conditionally installs Rust and Node.

192 Rust tests, 274 frontend tests, both builds clean, zero warnings.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

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

@@ -389,13 +389,30 @@
   let relayLastAt = 0;
   let relayHideTimer = null;
 
+  // ─── shared-url-sanitizer ─────────────────────────────────────
+  // THIS IS A COPY OF `sanitizeRelayUrl` IN app/src/lib/urlRelay.ts.
+  // It exists only because this file is embedded standalone via include_str!()
+  // and cannot import a module. Change one, change the other — and note that
+  // app/src/lib/urlRelay.embedded.test.ts reads this file, extracts the block
+  // between these two markers and runs it against the same table of cases as
+  // the TypeScript original, so a divergence fails the suite instead of
+  // silently shipping. Keep the markers, the function name and the arity
+  // intact: that test finds the code by them.
   function sanitizeRelayUrl(raw) {
     if (typeof raw !== 'string') return null;
     const s = raw.trim();
     if (!s || s.length > RELAY_MAX_URL) return null;
     // Control characters and whitespace first: new URL() strips tabs/newlines,
-    // so "java\nscript:" would otherwise slip through as javascript:.
-    if (/[\s\u0000-\u0020\u007f]/.test(s)) return null;
+    // so "java\nscript:" would otherwise slip through as javascript:. Quotes
+    // and backticks go with them — all three are illegal in a URL, and this
+    // string ends up as an argument to something that may treat them as syntax.
+    for (const ch of s) {
+      const code = ch.codePointAt(0);
+      if (code <= 0x20 || code === 0x7f) return null;
+      if (code >= 0x80 && code <= 0x9f) return null;
+      if (ch === '"' || ch === "'" || ch === '`') return null;
+      if (ch.trim() === '') return null;
+    }
     let u;
     try { u = new URL(s); } catch (e) { return null; }
     if (u.protocol !== 'http:' && u.protocol !== 'https:') return null;
@@ -403,6 +420,7 @@
     if (u.username || u.password) return null;  // origin spoofing
     return u.toString();
   }
+  // ─── end shared-url-sanitizer ────────────────────────────────
 
   function parseRelayOsc(data) {
     if (typeof data !== 'string') return null;