feat: Optimize theme data handling and simplify widget structure in NotesApp

lib/app.dart

@@ -102,6 +102,7 @@ class _NotesAppState extends State<NotesApp>
 
     setState(() {
       _themeSeedColor = Color(storedColorValue);
+      _themeData = AppTheme.theme(seedColor: _themeSeedColor);
     });
   }
 
@@ -115,10 +116,14 @@ class _NotesAppState extends State<NotesApp>
 
     setState(() {
       _themeSeedColor = color;
+      _themeData = AppTheme.theme(seedColor: _themeSeedColor);
     });
   }
 
-  ThemeData get _theme => AppTheme.theme(seedColor: _themeSeedColor);
+  // Cached ThemeData to avoid recomputing on every build.
+  ThemeData? _themeData;
+
+  ThemeData get _theme => _themeData ??= AppTheme.theme(seedColor: _themeSeedColor);
 
   @override
   void didChangeAppLifecycleState(AppLifecycleState state) {
@@ -767,12 +772,7 @@ class _NotesAppState extends State<NotesApp>
   }
 
   Widget _buildLoadingScreen() {
-    return MaterialApp(
+    return const Scaffold(
-      navigatorKey: _navigatorKey,
-      title: 'Mis Notas',
-      debugShowCheckedModeBanner: false,
-      theme: _theme,
-      home: const Scaffold(
       body: SafeArea(
         child: Column(
           children: [
@@ -791,19 +791,11 @@ class _NotesAppState extends State<NotesApp>
           ],
         ),
       ),
-      ),
     );
   }
 
   Widget _buildAppShell({required Widget home}) {
-    return MaterialApp(
+    return home;
-      navigatorKey: _navigatorKey,
-      title: 'Mis Notas',
-      debugShowCheckedModeBanner: false,
-      scaffoldMessengerKey: _scaffoldMessengerKey,
-      theme: _theme,
-      home: home,
-    );
   }
 
   Widget _buildMainShell(NoteRepository repository) {
@@ -829,13 +821,7 @@ class _NotesAppState extends State<NotesApp>
             onThemeColorSelected: _setThemeSeedColor,
           );
 
-    return MaterialApp(
+    return Shortcuts(
-      navigatorKey: _navigatorKey,
-      title: 'Mis Notas',
-      debugShowCheckedModeBanner: false,
-      scaffoldMessengerKey: _scaffoldMessengerKey,
-      theme: _theme,
-      home: Shortcuts(
       shortcuts: <LogicalKeySet, Intent>{
         LogicalKeySet(LogicalKeyboardKey.f5): const PerformSyncIntent(),
       },
@@ -897,7 +883,6 @@ class _NotesAppState extends State<NotesApp>
           ),
         ),
       ),
-      ),
     );
   }
 
@@ -951,21 +936,22 @@ class _NotesAppState extends State<NotesApp>
 
   @override
   Widget build(BuildContext context) {
-    if (_isBootstrapping) {
+    Widget homeWidget;
-      return _buildLoadingScreen();
-    }
 
+    if (_isBootstrapping) {
+      homeWidget = _buildLoadingScreen();
+    } else {
       final NoteRepository? repository = _repository;
 
       if (repository != null) {
-      return _buildMainShell(repository);
+        homeWidget = _buildMainShell(repository);
-    }
+      } else {
-
         switch (_phase) {
           case _AppPhase.loading:
-        return _buildLoadingScreen();
+            homeWidget = _buildLoadingScreen();
+            break;
           case _AppPhase.access:
-        return _buildAppShell(
+            homeWidget = _buildAppShell(
               home: VaultAccessScreen(
                 isBusy: _isUnlocking,
                 onCreateAccountPressed: (String email, String password) async {
@@ -985,8 +971,9 @@ class _NotesAppState extends State<NotesApp>
                 onContinueWithoutAccount: _enterWithoutAccount,
               ),
             );
+            break;
           case _AppPhase.biometricChoice:
-        return _buildAppShell(
+            homeWidget = _buildAppShell(
               home: BiometricChoiceScreen(
                 isBusy: _isUnlocking,
                 onEnableBiometrics: () =>
@@ -995,20 +982,30 @@ class _NotesAppState extends State<NotesApp>
                     _completeBiometricChoice(enableBiometrics: false),
               ),
             );
+            break;
           case _AppPhase.biometricGate:
-        return _buildAppShell(
+            homeWidget = _buildAppShell(
               home: BiometricGateScreen(
                 key: ValueKey<int>(_biometricGateSession),
                 isBusy: _isUnlocking,
                 onUnlockRequested: _unlockBiometricGate,
               ),
             );
+            break;
           case _AppPhase.notes:
-        if (repository == null) {
+            homeWidget = _buildLoadingScreen();
-          return _buildLoadingScreen();
+            break;
+        }
+      }
     }
 
-        return _buildMainShell(repository);
+    return MaterialApp(
-    }
+      navigatorKey: _navigatorKey,
+      title: 'Mis Notas',
+      debugShowCheckedModeBanner: false,
+      scaffoldMessengerKey: _scaffoldMessengerKey,
+      theme: _theme,
+      home: homeWidget,
+    );
   }
 }