Initial commit: Fabled Android app

Flutter Android client for FabledAssistant with:
- Session-cookie auth via persistent cookie jar (Dio + cookie_jar)
- OAuth/SSO login via in-app WebView (flutter_inappwebview)
- Notes: list, detail (markdown render), create/edit
- Tasks: list with status tabs, create/edit with priority
- Chat: SSE streaming bubbles, conversation management
- Quick Capture FAB for rapid note/task creation
- Settings screen (change server URL, logout)
- Android home screen widget → opens chat
- Riverpod state management, go_router navigation

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

lib/data/models/message.dart

@@ -0,0 +1,39 @@
+enum MessageRole { user, assistant }
+
+class Message {
+  final int? id;
+  final int conversationId;
+  final MessageRole role;
+  final String content;
+  final String status; // "complete" | "generating"
+  final DateTime? createdAt;
+
+  const Message({
+    this.id,
+    required this.conversationId,
+    required this.role,
+    required this.content,
+    this.status = 'complete',
+    this.createdAt,
+  });
+
+  factory Message.fromJson(Map<String, dynamic> json) => Message(
+        id: json['id'] as int?,
+        conversationId: json['conversation_id'] as int,
+        role: json['role'] == 'user' ? MessageRole.user : MessageRole.assistant,
+        content: json['content'] as String,
+        status: json['status'] as String? ?? 'complete',
+        createdAt: json['created_at'] != null
+            ? DateTime.parse(json['created_at'] as String)
+            : null,
+      );
+
+  Message copyWith({String? content, String? status}) => Message(
+        id: id,
+        conversationId: conversationId,
+        role: role,
+        content: content ?? this.content,
+        status: status ?? this.status,
+        createdAt: createdAt,
+      );
+}