Merge origin/main (v1.65.0.0 fork port wave 2) into test-evals-ci-speedup

Second overlapping-wave merge; resolutions compose intent:

- TEST_ROOTS: ours is the superset (main also wired ios-qa/daemon/test;
  ours additionally has ios-qa/scripts + browser-skills). package.json
  'test' keeps routing through the canonical strict runner.
- gbrainAvailable: main fixed the same load-flake with a strictly better
  mechanism (memoized stat-based PATH scan, no subprocess at all) —
  theirs supersedes this branch's memoized-exec probe. Main also made
  the query timeout env-overridable (GSTACK_BRAIN_TIMEOUT_MS).
- Model defaults: adopted main's lib/eval-model.ts abstraction (one
  resolution point, env-overridable per kind) and applied decision D1a
  inside it: capture defaults to Sonnet (Opus opt-in via explicit arg or
  GSTACK_EVAL_MODEL_CAPTURE); test pins updated to follow.
- Parent watchdog: main's rewrite (named parameterized tick, driven
  deterministically by its test via __testInternals__, plus handoff
  suppression semantics from session persistence) supersedes this
  branch's env-tunable interval; adopted their server + test wholesale.
- windows-free-tests: ours (curated bun run test:windows) — main's
  hand-list grew by one more file, which the curated runner subsumes
  automatically; that drift is the reason for D11.
- context-skills 0-for-26 fix: both waves made the IDENTICAL fix; kept
  this branch's comment (carries the receipts).
- .gitignore: main's superset (also ignores Package.resolved — their
  never-commit call; untracked the copy this branch had committed).

Verified: 239-test merge battery green, watchdog 8/8, eval-model 5/5,
actionlint clean, eval:select works.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

browse/test/extension-sender-auth.test.ts

@@ -32,9 +32,13 @@ const CONTENT_SCRIPT_SENDER = { id: OWN_ID, url: 'https://evil.example/page', ta
 const FOREIGN_SENDER = { id: FOREIGN_ID, url: `chrome-extension://${FOREIGN_ID}/background.html` };
 const NO_URL_SENDER = { id: OWN_ID };
 
+// 'sidebar-command' is no longer a message type at all — the chat-queue path
+// was ripped along with the /sidebar-command endpoint, so background.js now
+// rejects it pre-gate as an unknown type (no response, nothing to leak). It is
+// pinned separately below as a representative unknown type.
 const PRIVILEGED = [
   'getPort', 'setPort', 'getServerUrl', 'getToken', 'fetchRefs',
-  'command', 'sidebar-command', 'getTabState',
+  'command', 'getTabState',
 ];
 // Content-script-originated flows that must keep working.
 const CONTENT_SCRIPT_TYPES = ['openSidePanel', 'elementPicked', 'pickerCancelled', 'inspectResult'];
@@ -216,6 +220,16 @@ describe('background.js onMessage listener (behavioral)', () => {
     }
   });
 
+  test('retired sidebar-command type is rejected pre-gate with no response and no leaks', () => {
+    // Even from the most-trusted sender shape, a type outside ALLOWED_TYPES
+    // never reaches a handler: no sendResponse, no token/port fields possible.
+    for (const sender of [PAGE_SENDER, CONTENT_SCRIPT_SENDER, FOREIGN_SENDER, NO_URL_SENDER]) {
+      const r = dispatch(listener, { type: 'sidebar-command', message: 'hi' }, sender);
+      expect(r.responded).toBe(false);
+      expectDenied(r);
+    }
+  });
+
   test('denied setPort never persists the attacker port', () => {
     const before = calls.storageSet.length;
     const r = dispatch(listener, { type: 'setPort', port: 6666 }, CONTENT_SCRIPT_SENDER);