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/features/chat/di/chat_bot_provider.dart

@@ -3,9 +3,6 @@ import 'package:im_app/app/di/db_provider.dart';
 import 'package:im_app/data/repositories/chat_bot_repository_impl.dart';
 import 'package:im_app/domain/entities/chat_bot.dart';
 import 'package:im_app/domain/repositories/chat_bot_repository.dart';
-import 'package:riverpod_annotation/riverpod_annotation.dart';
-
-part 'chat_bot_provider.g.dart';
 
 // ── Repository ────────────────────────────────────────────────────────────────
 
@@ -17,13 +14,11 @@ final chatBotRepositoryProvider = Provider<ChatBotRepository>((ref) {
 // ── Streams ───────────────────────────────────────────────────────────────────
 
 /// 监听所有聊天机器人
-@riverpod
-Stream<List<ChatBot>> allChatBots(Ref ref) {
+final allChatBotsProvider = StreamProvider<List<ChatBot>>((ref) {
   return ref.watch(chatBotRepositoryProvider).watchAllChatBots();
-}
+});
 
 /// 监听指定聊天机器人
-@riverpod
-Stream<ChatBot?> chatBot(Ref ref, int id) {
+final chatBotProvider = StreamProvider.family<ChatBot?, int>((ref, id) {
   return ref.watch(chatBotRepositoryProvider).watchChatBot(id);
-}
+});

apps/im_app/lib/features/chat/di/chat_category_provider.dart

@@ -3,9 +3,6 @@ import 'package:im_app/app/di/db_provider.dart';
 import 'package:im_app/data/repositories/chat_category_repository_impl.dart';
 import 'package:im_app/domain/entities/chat_category.dart';
 import 'package:im_app/domain/repositories/chat_category_repository.dart';
-import 'package:riverpod_annotation/riverpod_annotation.dart';
-
-part 'chat_category_provider.g.dart';
 
 // ── Repository ────────────────────────────────────────────────────────────────
 
@@ -17,13 +14,11 @@ final chatCategoryRepositoryProvider = Provider<ChatCategoryRepository>((ref) {
 // ── Streams ───────────────────────────────────────────────────────────────────
 
 /// 监听所有聊天分类
-@riverpod
-Stream<List<ChatCategory>> allChatCategories(Ref ref) {
+final allChatCategoriesProvider = StreamProvider<List<ChatCategory>>((ref) {
   return ref.watch(chatCategoryRepositoryProvider).watchAllChatCategories();
-}
+});
 
 /// 监听指定聊天分类
-@riverpod
-Stream<ChatCategory?> chatCategory(Ref ref, int id) {
+final chatCategoryProvider = StreamProvider.family<ChatCategory?, int>((ref, id) {
   return ref.watch(chatCategoryRepositoryProvider).watchChatCategory(id);
-}
+});

apps/im_app/lib/features/chat/di/chat_provider.dart

@@ -3,9 +3,6 @@ import 'package:im_app/app/di/db_provider.dart';
 import 'package:im_app/data/repositories/chat_repository_impl.dart';
 import 'package:im_app/domain/entities/chat.dart';
 import 'package:im_app/domain/repositories/chat_repository.dart';
-import 'package:riverpod_annotation/riverpod_annotation.dart';
-
-part 'chat_provider.g.dart';
 
 // ── Repository ────────────────────────────────────────────────────────────────
 
@@ -17,13 +14,11 @@ final chatRepositoryProvider = Provider<ChatRepository>((ref) {
 // ── Streams ───────────────────────────────────────────────────────────────────
 
 /// 监听所有聊天
-@riverpod
-Stream<List<Chat>> allChats(Ref ref) {
+final allChatsProvider = StreamProvider<List<Chat>>((ref) {
   return ref.watch(chatRepositoryProvider).watchAllChats();
-}
+});
 
 /// 监听指定聊天
-@riverpod
-Stream<Chat?> chat(Ref ref, int id) {
+final chatProvider = StreamProvider.family<Chat?, int>((ref, id) {
   return ref.watch(chatRepositoryProvider).watchChat(id);
-}
+});

apps/im_app/lib/features/chat/di/chat_service_providers.dart

@@ -0,0 +1,66 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+import 'package:im_app/app/di/app_providers.dart';
+import 'package:im_app/app/di/network_provider.dart';
+import 'package:im_app/core/services/ws_message_service.dart';
+import 'package:im_app/features/chat/di/chat_provider.dart';
+import 'package:im_app/features/chat/di/message_provider.dart';
+import 'package:im_app/features/chat/usecases/fetch_history_use_case.dart';
+import 'package:im_app/features/chat/usecases/send_message_use_case.dart';
+
+/// ## DI 装配：Chat 服务层
+///
+/// 负责装配：
+/// - [WsMessageService] — WS 帧接收 + HTTP 补拉 + DB 写入
+/// - [SendMessageUseCase] — 发送文本消息
+/// - [FetchHistoryUseCase] — 主动拉取历史
+///
+/// WS 消息服务在 Provider 创建时自动调用 `start()`，
+/// Provider dispose 时调用 `stop()`，生命周期与 Riverpod 容器绑定。
+
+// ── WsMessageService ──────────────────────────────────────────────────────────
+
+/// WS 消息服务 Provider
+///
+/// 全局单例，随应用启动而创建，登出时随 ProviderContainer 一同销毁。
+/// 创建后立即调用 [WsMessageService.start]，订阅 SocketManager.messageStream。
+final wsMessageServiceProvider = Provider<WsMessageService>((ref) {
+  final service = WsMessageService(
+    socketManager: ref.read(socketManagerProvider),
+    apiClient: ref.read(networkSdkApiProvider),
+    messageRepo: ref.read(messageRepositoryProvider),
+    chatRepo: ref.read(chatRepositoryProvider),
+  );
+
+  service.start();
+
+  ref.onDispose(service.stop);
+
+  return service;
+});
+
+// ── SendMessageUseCase ────────────────────────────────────────────────────────
+
+/// 发送消息用例 Provider
+///
+/// [currentUid] 从 [authNotifierProvider] 获取，用于填写发送方 uid。
+/// uid 为 null（未登录）时用例仍可创建，但发送时 sendId = 0。
+final sendMessageUseCaseProvider = Provider<SendMessageUseCase>((ref) {
+  final uid = ref.read(authNotifierProvider).currentUid ?? 0;
+  return SendMessageUseCase(
+    apiClient: ref.read(networkSdkApiProvider),
+    messageRepo: ref.read(messageRepositoryProvider),
+    chatRepo: ref.read(chatRepositoryProvider),
+    currentUid: uid,
+  );
+});
+
+// ── FetchHistoryUseCase ───────────────────────────────────────────────────────
+
+/// 拉取历史消息用例 Provider
+final fetchHistoryUseCaseProvider = Provider<FetchHistoryUseCase>((ref) {
+  return FetchHistoryUseCase(
+    apiClient: ref.read(networkSdkApiProvider),
+    messageRepo: ref.read(messageRepositoryProvider),
+  );
+});

apps/im_app/lib/features/chat/di/group_provider.dart

@@ -3,9 +3,6 @@ import 'package:im_app/app/di/db_provider.dart';
 import 'package:im_app/data/repositories/group_repository_impl.dart';
 import 'package:im_app/domain/entities/group.dart';
 import 'package:im_app/domain/repositories/group_repository.dart';
-import 'package:riverpod_annotation/riverpod_annotation.dart';
-
-part 'group_provider.g.dart';
 
 // ── Repository ────────────────────────────────────────────────────────────────
 
@@ -17,13 +14,11 @@ final groupRepositoryProvider = Provider<GroupRepository>((ref) {
 // ── Streams ───────────────────────────────────────────────────────────────────
 
 /// 监听所有群组
-@riverpod
-Stream<List<Group>> allGroups(Ref ref) {
+final allGroupsProvider = StreamProvider<List<Group>>((ref) {
   return ref.watch(groupRepositoryProvider).watchAll();
-}
+});
 
 /// 监听指定群组
-@riverpod
-Stream<Group?> groupById(Ref ref, int id) {
+final groupByIdProvider = StreamProvider.family<Group?, int>((ref, id) {
   return ref.watch(groupRepositoryProvider).watchById(id);
-}
+});

apps/im_app/lib/features/chat/di/message_provider.dart

@@ -3,9 +3,6 @@ import 'package:im_app/app/di/db_provider.dart';
 import 'package:im_app/data/repositories/message_repository_impl.dart';
 import 'package:im_app/domain/entities/message.dart';
 import 'package:im_app/domain/repositories/message_repository.dart';
-import 'package:riverpod_annotation/riverpod_annotation.dart';
-
-part 'message_provider.g.dart';
 
 // ── Repository ────────────────────────────────────────────────────────────────
 
@@ -17,13 +14,11 @@ final messageRepositoryProvider = Provider<MessageRepository>((ref) {
 // ── Streams ───────────────────────────────────────────────────────────────────
 
 /// 监听指定 chatId 的消息列表
-@riverpod
-Stream<List<Message>> messagesByChatId(Ref ref, int chatId) {
+final messagesByChatIdProvider = StreamProvider.family<List<Message>, int>((ref, chatId) {
   return ref.watch(messageRepositoryProvider).watchByChatId(chatId);
-}
+});
 
 /// 监听指定消息
-@riverpod
-Stream<Message?> messageById(Ref ref, int id) {
+final messageByIdProvider = StreamProvider.family<Message?, int>((ref, id) {
   return ref.watch(messageRepositoryProvider).watchById(id);
-}
+});