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/data/api/chat_api.dart

@@ -42,17 +42,18 @@ class ChatApi {
     }
   }
 
-  // Messages are embedded in the conversation detail response.
-  Future<List<Message>> getMessages(int conversationId) async {
+  // Returns the conversation metadata AND its messages in a single request.
+  Future<(Conversation, List<Message>)> getMessages(int conversationId) async {
     try {
       final response =
           await _dio.get('/api/chat/conversations/$conversationId');
       final conv = response.data as Map<String, dynamic>;
+      final conversation = Conversation.fromJson(conv);
       final list = conv['messages'] as List<dynamic>? ?? [];
-      return list
+      final messages = list
           .map((e) => Message.fromJson(e as Map<String, dynamic>))
-          .where((m) => m.status != 'generating') // skip in-flight placeholders
           .toList();
+      return (conversation, messages);
     } on DioException catch (e) {
       throw dioToApp(e);
     }
@@ -77,7 +78,12 @@ class ChatApi {
         '/api/chat/conversations/$conversationId/generation/stream',
         options: Options(
           responseType: ResponseType.stream,
-          headers: {'Accept': 'text/event-stream'},
+          receiveTimeout: Duration.zero, // SSE streams run indefinitely
+          sendTimeout: Duration.zero,
+          headers: {
+            'Accept': 'text/event-stream',
+            'Cache-Control': 'no-cache',
+          },
         ),
       );
 
@@ -98,15 +104,19 @@ class ChatApi {
           if (line.startsWith('event: ')) {
             currentEvent = line.substring(7).trim();
           } else if (line.startsWith('data: ')) {
-            final jsonStr = line.substring(6).trim();
-            if (currentEvent == 'chunk') {
+            final data = line.substring(6).trim();
+            if (data == '[DONE]') return;
+            if (currentEvent == 'done' || currentEvent == 'error') return;
+
+            // Parse as JSON if possible, otherwise yield raw text.
+            if (currentEvent == 'chunk' || currentEvent.isEmpty) {
               try {
-                final data = json.decode(jsonStr) as Map<String, dynamic>;
-                final text = data['text'] as String? ?? '';
+                final obj = json.decode(data) as Map<String, dynamic>;
+                final text = obj['text'] as String? ?? '';
                 if (text.isNotEmpty) yield text;
-              } catch (_) {}
-            } else if (currentEvent == 'done' || currentEvent == 'error') {
-              return;
+              } catch (_) {
+                if (data.isNotEmpty) yield data;
+              }
             }
           } else if (line.isEmpty) {
             currentEvent = ''; // blank line = SSE event separator

lib/data/api/quick_capture_api.dart

@@ -0,0 +1,49 @@
+import 'package:dio/dio.dart';
+
+import 'api_client.dart';
+
+/// Result returned by POST /api/quick-capture.
+/// type is one of: "note", "task", "event", "todo"
+class CaptureResult {
+  final String type;
+  final String message; // human-readable summary from the server
+  final bool fallback;  // true when the server used a note as a fallback
+  final int? id;
+  final String title;
+
+  const CaptureResult({
+    required this.type,
+    required this.message,
+    this.fallback = false,
+    this.id,
+    required this.title,
+  });
+
+  factory CaptureResult.fromJson(Map<String, dynamic> json) {
+    final data = json['data'] as Map<String, dynamic>? ?? {};
+    return CaptureResult(
+      type: json['type'] as String? ?? 'note',
+      message: json['message'] as String? ?? '',
+      fallback: json['fallback'] as bool? ?? false,
+      id: data['id'] as int?,
+      title: data['title'] as String? ?? '',
+    );
+  }
+}
+
+class QuickCaptureApi {
+  final Dio _dio;
+  const QuickCaptureApi(this._dio);
+
+  Future<CaptureResult> capture(String text) async {
+    try {
+      final response = await _dio.post(
+        '/api/quick-capture',
+        data: {'text': text},
+      );
+      return CaptureResult.fromJson(response.data as Map<String, dynamic>);
+    } on DioException catch (e) {
+      throw dioToApp(e);
+    }
+  }
+}