Reestructuracion de la app

lib/app.dart

@@ -79,6 +79,79 @@ class _NotesAppState extends State<NotesApp>
   ThemeData? _lightTheme;
   ThemeData? _darkTheme;
 
+  bool _isSyncBannerVisible() {
+    switch (_syncStatus) {
+      case SyncStatus.preparing:
+      case SyncStatus.encrypting:
+      case SyncStatus.uploading:
+      case SyncStatus.waitingResponse:
+      case SyncStatus.decrypting:
+      case SyncStatus.syncing:
+        return true;
+      case SyncStatus.idle:
+      case SyncStatus.synced:
+      case SyncStatus.error:
+        return false;
+    }
+  }
+
+  Widget _buildSyncBanner(BuildContext context) {
+    if (!_isSyncBannerVisible()) {
+      return const SizedBox.shrink();
+    }
+
+    final AppPalette palette = _activePalette();
+    final String message = _syncErrorMessage ?? _syncDetailMessage ?? 'Sincronizando...';
+    final double? progress = _syncProgress;
+
+    return Material(
+      color: palette.surfaceElevated,
+      elevation: 12,
+      child: SafeArea(
+        top: false,
+        child: Container(
+          padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 10),
+          decoration: BoxDecoration(
+            border: Border(top: BorderSide(color: palette.border)),
+          ),
+          child: Column(
+            mainAxisSize: MainAxisSize.min,
+            crossAxisAlignment: CrossAxisAlignment.stretch,
+            children: [
+              Row(
+                children: [
+                  Icon(Icons.cloud_sync_outlined, color: palette.textSecondary, size: 18),
+                  const SizedBox(width: 10),
+                  Expanded(
+                    child: Text(
+                      message,
+                      maxLines: 1,
+                      overflow: TextOverflow.ellipsis,
+                      style: TextStyle(
+                        color: palette.textPrimary,
+                        fontSize: 13,
+                        fontWeight: FontWeight.w600,
+                      ),
+                    ),
+                  ),
+                ],
+              ),
+              const SizedBox(height: 8),
+              ClipRRect(
+                borderRadius: BorderRadius.circular(999),
+                child: LinearProgressIndicator(
+                  minHeight: 4,
+                  value: progress,
+                  backgroundColor: palette.borderMuted,
+                ),
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+
   Brightness _effectiveBrightness() {
     switch (_themeMode) {
       case ThemeMode.dark:
@@ -964,6 +1037,10 @@ class _NotesAppState extends State<NotesApp>
                         child: activeScreen,
                       ),
                     ),
+                    AnimatedSwitcher(
+                      duration: const Duration(milliseconds: 180),
+                      child: _buildSyncBanner(context),
+                    ),
                   ],
                 ),
               ),