Major improvements: Firebase data migration, enhanced loading screens, multi-day prayer tracking

- Migrated all localStorage data to Firebase for cross-device sync
  - Prayer drafts now stored in users/{userId}/drafts
  - Reminder settings in users/{userId}/settings
  - Prayer statistics in users/{userId}/statistics
- Implemented persistent 'most prayed for' tracking in Firebase
- Enhanced loading screen with animated backgrounds and gradients
- Fixed auth session restoration on hard refresh
- Added prayedDates array for multi-day prayer tracking
- Calendar now accurately shows all days a prayer was prayed for
- Enabled Firestore offline persistence for offline-first experience
- Updated Firestore security rules for new data structure
- Improved clock display (removed leading zero from hours)
- Moved clock below date on homepage with appropriate sizing
- Fixed data loading race conditions between auth and Firestore

src/lib/firebase.ts

@@ -1,7 +1,7 @@
 // Import the functions you need from the SDKs you need
 import { initializeApp } from 'firebase/app';
 import { getAuth } from 'firebase/auth';
-import { getFirestore } from 'firebase/firestore';
+import { getFirestore, enableIndexedDbPersistence, enableMultiTabIndexedDbPersistence } from 'firebase/firestore';
 import { getStorage } from 'firebase/storage';
 import { getAnalytics } from 'firebase/analytics';
 import { getMessaging, onMessage, getToken } from 'firebase/messaging';
@@ -29,6 +29,19 @@ export const auth = getAuth(app);
 // Initialize Cloud Firestore and get a reference to the service
 export const db = getFirestore(app);
 
+// Enable offline persistence
+if (typeof window !== 'undefined') {
+  enableMultiTabIndexedDbPersistence(db).catch((err) => {
+    if (err.code === 'failed-precondition') {
+      // Multiple tabs open, persistence can only be enabled in one tab at a time
+      console.warn('Firestore: Multiple tabs open, persistence disabled');
+    } else if (err.code === 'unimplemented') {
+      // The current browser doesn't support persistence
+      console.warn('Firestore: Persistence not supported in this browser');
+    }
+  });
+}
+
 // Initialize Firebase Storage and get a reference to the service
 export const storage = getStorage(app);