test: add Phase C E2E tests and fix pre-existing test failures

- Add phase-c.test.ts: 27 new E2E tests across 11 scenarios covering
  hardening sprint features (command palette, search overlay, notification
  center, keyboard navigation, settings panel, project health, metrics tab,
  context tab, files tab, LLM-judged settings/status bar)
- Fix 3 pre-existing failures in bterminal.test.ts: update stale CSS
  selectors (.group-name → .cmd-label, .palette-item.active → .selected)
- Register phase-c.test.ts in wdio.conf.js specs array
- Update test counts: 444 vitest + 151 cargo + 109 E2E = 704 total

v2/tests/e2e/wdio.conf.js

@@ -29,6 +29,7 @@ export const config = {
     resolve(__dirname, 'specs/bterminal.test.ts'),
     resolve(__dirname, 'specs/agent-scenarios.test.ts'),
     resolve(__dirname, 'specs/phase-b.test.ts'),
+    resolve(__dirname, 'specs/phase-c.test.ts'),
   ],
 
   // ── Capabilities ──