fix(browse): write self-contained .gstack/.gitignore unconditionally

ensureStateDir only appended .gstack/ to the project .gitignore when that file
already existed, skipped silently on ENOENT, and swallowed other append
failures. With BROWSE_PERSIST_STATE=1, session-state.json (live cookies +
localStorage/sessionStorage tokens) and browse-network.log / browse-audit.jsonl
(request headers) then sat git-add-able under <git-root>/.gstack/. Write a
self-contained <stateDir>/.gitignore containing "*" unconditionally, before
return, so the state dir's contents can never be committed regardless of the
project .gitignore. The project-.gitignore append is kept as redundant safety.

The no-import-side-effects guard is relaxed to allow exactly this lone
.gitignore guard file (still fails on browse.json / session-state.json / logs /
listener binds) — the guard is written eagerly by ensureStateDir at import and
is not leaked state.

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

browse/src/config.ts

@@ -114,6 +114,20 @@ export function ensureStateDir(config: BrowseConfig): void {
     throw err;
   }
 
+  // Load-bearing guard: a self-contained ignore INSIDE the state dir so its
+  // contents can NEVER be `git add`-ed, regardless of the project's own
+  // .gitignore (which may be absent, or the append below may silently fail).
+  // The state dir holds session-state.json (live cookies + localStorage/
+  // sessionStorage tokens) and browse-network.log / browse-audit.jsonl
+  // (captured request headers can carry bearer tokens). Written unconditionally,
+  // synchronously, before return — the project-.gitignore dance below is now
+  // redundant safety, kept so `.gstack/` still reads as ignored in git status.
+  try {
+    fs.writeFileSync(path.join(config.stateDir, '.gitignore'), '*\n');
+  } catch {
+    // Best-effort; the project-.gitignore path below is the fallback.
+  }
+
   // Ensure .gstack/ is in the project's .gitignore
   // First, check if git already ignores .gstack/ (via global excludes, .git/info/exclude, or parent .gitignore)
   if (isIgnoredByGit(config.projectDir, '.gstack/')) return;

browse/test/config.test.ts

@@ -61,6 +61,21 @@ describe('config', () => {
       fs.rmSync(tmpDir, { recursive: true, force: true });
     });
 
+    test('writes a self-contained .gstack/.gitignore with * unconditionally', () => {
+      // Even with NO project .gitignore, the state dir must carry its own
+      // ignore so persisted cookies / network+audit logs can never be git-added.
+      const tmpDir = path.join(os.tmpdir(), `browse-selfignore-test-${Date.now()}`);
+      fs.mkdirSync(tmpDir, { recursive: true });
+      const config = resolveConfig({ BROWSE_STATE_FILE: path.join(tmpDir, '.gstack', 'browse.json') });
+      ensureStateDir(config);
+      const selfIgnore = path.join(config.stateDir, '.gitignore');
+      expect(fs.existsSync(selfIgnore)).toBe(true);
+      expect(fs.readFileSync(selfIgnore, 'utf-8')).toBe('*\n');
+      // No nesting: the ignore is directly inside the state dir, not .gstack/.gstack/.
+      expect(fs.existsSync(path.join(config.stateDir, '.gstack'))).toBe(false);
+      fs.rmSync(tmpDir, { recursive: true, force: true });
+    });
+
     test('adds .gstack/ to .gitignore if not present', () => {
       const tmpDir = path.join(os.tmpdir(), `browse-gitignore-test-${Date.now()}`);
       fs.mkdirSync(tmpDir, { recursive: true });

browse/test/server-no-import-side-effects.test.ts

@@ -42,9 +42,13 @@ const sigtermAfter = process.listenerCount('SIGTERM');
 const uncaughtAfter = process.listenerCount('uncaughtException');
 
 // Check that the gstack home directory wasn't populated as a side effect.
+// A lone \`.gitignore\` (the state-dir ignore guard, contents "*") is expected
+// and is NOT leaked state — ensureStateDir writes it so persisted cookies/logs
+// can never be git-committed. Any OTHER entry (browse.json, session-state.json,
+// logs) would be a real auto-start write and must still fail the guard.
 let gstackPopulated = false;
 try {
-  const entries = fs.readdirSync(${JSON.stringify(tmpGstack)});
+  const entries = fs.readdirSync(${JSON.stringify(tmpGstack)}).filter(e => e !== '.gitignore');
   gstackPopulated = entries.length > 0;
 } catch {
   // Doesn't exist — that's the win we want.