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
9a90c2499a