fix(13-02): resolve residual no-unnecessary-type-assertion in SyncStateToast.test

- Replace inline 'as string | null' assertion with an explicit typed const
  declaration inside the vi.hoisted() callback body
- 'value: string | null' typed const satisfies both ESLint (no assertion) and
  tsc (null assignment on line 82 is type-safe)

apps/pwa/src/components/SyncStateToast.test.tsx

@@ -25,11 +25,15 @@ const {
   mockLastSyncedUid,
   mockSetLastSyncedUid,
   mockFetchSyncStatus,
-} = vi.hoisted(() => ({
-  mockLastSyncedUid: { value: 'test-uid-123' as string | null },
-  mockSetLastSyncedUid: vi.fn(),
-  mockFetchSyncStatus: vi.fn(),
-}))
+} = vi.hoisted(() => {
+  // Declare with explicit type so later null assignments (line 82+) stay type-safe
+  const mockLastSyncedUid: { value: string | null } = { value: 'test-uid-123' }
+  return {
+    mockLastSyncedUid,
+    mockSetLastSyncedUid: vi.fn(),
+    mockFetchSyncStatus: vi.fn(),
+  }
+})
 
 vi.mock('../store/calendarStore.js', () => ({
   useCalendarStore: (selector: (s: Record<string, unknown>) => unknown) => {