Fix E2E test reliability issues and stale data bugs

- Fix race conditions: Set workers: 1 since all tests share test user state
- Fix stale data: GET /api/user and /api/cycle/current now fetch fresh data
  from database instead of returning stale PocketBase auth store cache
- Fix timing: Replace waitForTimeout with retry-based Playwright assertions
- Fix mobile test: Use exact heading match to avoid strict mode violation
- Add test user setup: Include notificationTime and update rule for users

All 1014 unit tests and 190 E2E tests pass.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

IMPLEMENTATION_PLAN.md

@@ -147,6 +147,11 @@ These are optional enhancements to improve E2E coverage. Not required for featur
 
 ## Revision History
 
+- 2026-01-13: Fixed E2E test reliability issues:
+  - Race conditions: Changed to single worker execution (tests share test user state)
+  - Stale data: GET /api/user and GET /api/cycle/current now fetch fresh data from database instead of stale auth cache
+  - Timing: Replaced fixed waitForTimeout calls with retry-based Playwright assertions
+  - Mobile test: Fixed strict mode violation by using exact heading match
 - 2026-01-13: Marked notifications.spec.ts as redundant (notification preferences already covered in settings.spec.ts)
 - 2026-01-13: Added dark-mode.spec.ts with 2 E2E tests (system preference detection for light/dark mode)
 - 2026-01-13: Added 4 Garmin E2E tests (network error recovery for save, disconnect, status fetch, retry)