feat: Add refresh token mechanism and sync request handling in home screen

lib/app.dart

@@ -70,6 +70,7 @@ class _NotesAppState extends State<NotesApp>
   _AppSection _currentSection = _AppSection.home;
   SyncStatus _syncStatus = SyncStatus.idle;
   String? _syncErrorMessage;
+  int _homeRefreshToken = 0;
 
   @override
   void initState() {
@@ -613,6 +614,10 @@ class _NotesAppState extends State<NotesApp>
       return;
     }
 
+    if (_syncStatus == SyncStatus.syncing) {
+      return;
+    }
+
     setState(() {
       _syncStatus = SyncStatus.syncing;
       _syncErrorMessage = null;
@@ -634,6 +639,7 @@ class _NotesAppState extends State<NotesApp>
         setState(() {
           _syncStatus = SyncStatus.synced;
           _syncErrorMessage = null;
+          _homeRefreshToken += 1;
         });
 
         // Reset to idle after 3 seconds
@@ -704,9 +710,11 @@ class _NotesAppState extends State<NotesApp>
             key: const ValueKey<String>('home-screen'),
             repository: repository,
             onOpenSettings: _openSettings,
+            onRequestSync: _performSync,
             onVaultInvalid: _resetLocalVaultData,
             syncStatus: _syncStatus,
             syncErrorMessage: _syncErrorMessage,
+            refreshToken: _homeRefreshToken,
           )
         : SettingsScreen(
             key: const ValueKey<String>('settings-screen'),