feat(chat): 发收消息全量实现 (#25~#28)

- 移除 @riverpod/@freezed 注解依赖，全部改为手写 Provider（无需 build_runner）
  · LoginState 改为纯 Dart，LoginViewModel/ThemeViewModel/ChatViewModel 改为 Notifier
  · UserNotifier 改为 FamilyAsyncNotifier<User?,int>，mini_app_provider 改为手写 Provider
  · 15 个 StreamProvider/StreamProvider.family 从 @riverpod 迁移至手写

- 发送消息（#25）
  · SendMessageRequest/SendMessageResponse DTO
  · SendMessageUseCase：乐观写入 DB → HTTP POST → 更新 Chat 摘要

- 接收消息 WS（#26）
  · WsMessageService：监听 mode2 WS 帧 → HTTP 补拉 → DB 写入 → Chat 更新
  · FetchHistoryRequest/FetchHistoryResponse DTO（GET /app/api/chat/history）
  · FetchHistoryUseCase：拉取 → insertOrReplaceAll

- DI 装配（chat_service_providers.dart）
  · wsMessageServiceProvider、sendMessageUseCaseProvider、fetchHistoryUseCaseProvider

- 聊天列表页（#27）
  · ChatListViewModel（Notifier<void>）+ chat_page.dart 真实会话列表 UI
  · ListTile：头像首字母、最新消息摘要、未读角标、时间格式化

- 聊天详情页（#28）
  · ChatDetailViewModel（FamilyNotifier<ChatDetailState,int>）+ chat_detail_page.dart
  · 消息气泡（自己/他人分左右）、底部输入框、发送状态与错误提示

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

apps/im_app/lib/data/remote/get_profile_request.dart

@@ -76,6 +76,26 @@ class ProfileResponse {
     required this.hint,
   });
 
+  factory ProfileResponse.fromJson(Map<String, dynamic> json) => ProfileResponse(
+    uid: (json['uid'] as num?)?.toInt() ?? 0,
+    uuid: json['uuid'] as String? ?? '',
+    lastOnline: (json['last_online'] as num?)?.toInt() ?? 0,
+    profilePic: json['profile_pic'] as String? ?? '',
+    profilePicGaussian: json['profile_pic_gaussian'] as String? ?? '',
+    nickname: json['nickname'] as String? ?? '',
+    contact: json['contact'] as String? ?? '',
+    countryCode: json['country_code'] as String? ?? '',
+    email: json['email'] as String? ?? '',
+    recoveryEmail: json['recovery_email'] as String? ?? '',
+    username: json['username'] as String? ?? '',
+    bio: json['bio'] as String? ?? '',
+    relationship: (json['relationship'] as num?)?.toInt() ?? 0,
+    userAlias: json['user_alias'] as String?,
+    channelId: (json['channel_id'] as num?)?.toInt() ?? 0,
+    channelGroupId: (json['channel_group_id'] as num?)?.toInt() ?? 0,
+    hint: json['hint'] as String? ?? '',
+  );
+
   User toEntity() => User(
     uid: uid,
     uuid: uuid,