Add search, offline queue, app icon, and UI polish

- Collapsible search in notes and tasks: magnifying glass in AppBar
  expands to a text field inline; close button resets the filter
- Offline capture queue: failed quick-captures (NetworkException) are
  persisted to SharedPreferences and retried automatically on next
  successful submit or app start; badge shows pending count
- App icon: book-with-sparkle logo from FabledAssistant SVG rendered
  at all Android densities with adaptive icon (indigo #6366f1 bg)
- Dark mode subtitle fix: use colorScheme.onSurfaceVariant for note
  preview and conversation timestamp text
- Remove swipe-to-delete (accidental deletions); long-press remains
- Chat: SSE streaming reliability, polling fallback, title patching
- Settings: theme toggle (system/light/dark) persisted to prefs
- Notes: delete button in edit screen; body preview in list
- Tasks: fix delete dialog context; description search support

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/screens/tasks/task_edit_screen.dart

@@ -85,14 +85,15 @@ class _TaskEditScreenState extends ConsumerState<TaskEditScreen> {
   Future<void> _delete() async {
     final confirm = await showDialog<bool>(
       context: context,
-      builder: (_) => AlertDialog(
+      builder: (dialogContext) => AlertDialog(
         title: const Text('Delete task?'),
+        content: Text(_titleController.text),
         actions: [
           TextButton(
-              onPressed: () => Navigator.pop(context, false),
+              onPressed: () => Navigator.pop(dialogContext, false),
               child: const Text('Cancel')),
           TextButton(
-              onPressed: () => Navigator.pop(context, true),
+              onPressed: () => Navigator.pop(dialogContext, true),
               child: const Text('Delete')),
         ],
       ),