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>

e2e/pocketbase-harness.ts

@@ -140,6 +140,12 @@ async function addUserFields(pb: PocketBase): Promise<void> {
  * Sets up API rules for collections to allow user access.
  */
 async function setupApiRules(pb: PocketBase): Promise<void> {
+  // Allow users to update their own user record
+  const usersCollection = await pb.collections.getOne("users");
+  await pb.collections.update(usersCollection.id, {
+    updateRule: "id = @request.auth.id",
+  });
+
   // Allow users to read/write their own period_logs
   const periodLogs = await pb.collections.getOne("period_logs");
   await pb.collections.update(periodLogs.id, {
@@ -202,6 +208,7 @@ async function createTestUser(
     verified: true,
     lastPeriodDate,
     cycleLength: 28,
+    notificationTime: "07:00",
     timezone: "UTC",
   });