feat(ui): git status indicator in the bottom bar, with a panel of uncommitted and unpushed work

Optional and per-device (showGitStatus, default off). GET /api/sessions/:id/git-status is
read-only and offline (no fetch, --no-optional-locks), skips remote and Docker sessions, caps its
lists, and single-flights concurrent polls. The toolbar indicator shows uncommitted files,
commits not pushed, or a check; clicking opens a draggable panel in the style of the Files window.

Which repositories: the enclosing one when there is one; otherwise every repository up to two
levels below the working directory (capped, skipping dot-folders and node_modules, never
following symlinks), each in a collapsible section, with the indicator summing them. A repository
that merely sits above the workspace and is the home folder or higher (a dotfiles repo) is
ignored. Git-supplied text is only ever written with textContent.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JrzFKEdBLwVfu6ev2ZscJS

config/test-suites.ts

@@ -35,6 +35,7 @@ export const BROWSER_TEST_GLOBS = [
   'test/shift-enter-keypress.browser.test.ts',
   'test/key-tester.browser.test.ts',
   'test/webhook-settings.browser.test.ts',
+  'test/git-status.browser.test.ts',
   'test/split-pane-orchestration.browser.test.ts',
   'test/split-pane-auto-collapse.browser.test.ts',
   'test/mobile-ime-preview.browser.test.ts',