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>

playwright.config.ts

@@ -22,8 +22,9 @@ export default defineConfig({
   // Retry failed tests on CI only
   retries: process.env.CI ? 2 : 0,
 
-  // Limit parallel workers on CI to avoid resource issues
-  workers: process.env.CI ? 1 : undefined,
+  // Run tests sequentially since all tests share the same test user
+  // Parallel execution causes race conditions when tests modify user state
+  workers: 1,
 
   // Reporter configuration
   reporter: [["html", { open: "never" }], ["list"]],