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>

src/app/api/user/route.test.ts

@@ -12,10 +12,28 @@ let currentMockUser: User | null = null;
 // Track PocketBase update calls
 const mockPbUpdate = vi.fn().mockResolvedValue({});
 
+// Track PocketBase getOne calls - returns the current mock user data
+const mockPbGetOne = vi.fn().mockImplementation(() => {
+  if (!currentMockUser) {
+    throw new Error("User not found");
+  }
+  return Promise.resolve({
+    id: currentMockUser.id,
+    email: currentMockUser.email,
+    garminConnected: currentMockUser.garminConnected,
+    lastPeriodDate: currentMockUser.lastPeriodDate?.toISOString(),
+    cycleLength: currentMockUser.cycleLength,
+    notificationTime: currentMockUser.notificationTime,
+    timezone: currentMockUser.timezone,
+    activeOverrides: currentMockUser.activeOverrides,
+  });
+});
+
 // Create mock PocketBase client
 const mockPb = {
   collection: vi.fn(() => ({
     update: mockPbUpdate,
+    getOne: mockPbGetOne,
   })),
 };
 
@@ -55,6 +73,7 @@ describe("GET /api/user", () => {
     vi.clearAllMocks();
     currentMockUser = null;
     mockPbUpdate.mockClear();
+    mockPbGetOne.mockClear();
   });
 
   it("returns user profile when authenticated", async () => {
@@ -133,6 +152,7 @@ describe("PATCH /api/user", () => {
     vi.clearAllMocks();
     currentMockUser = null;
     mockPbUpdate.mockClear();
+    mockPbGetOne.mockClear();
   });
 
   // Helper to create mock request with JSON body