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/contact/di/pending_friend_request_history_provider.dart

@@ -3,9 +3,6 @@ import 'package:im_app/app/di/db_provider.dart';
 import 'package:im_app/data/repositories/pending_friend_request_history_repository_impl.dart';
 import 'package:im_app/domain/entities/pending_friend_request_history.dart';
 import 'package:im_app/domain/repositories/pending_friend_request_history_repository.dart';
-import 'package:riverpod_annotation/riverpod_annotation.dart';
-
-part 'pending_friend_request_history_provider.g.dart';
 
 // ── Repository ────────────────────────────────────────────────────────────────
 
@@ -19,20 +16,13 @@ final pendingFriendRequestHistoryRepositoryProvider =
 // ── Streams ───────────────────────────────────────────────────────────────────
 
 /// 监听所有好友请求历史
-@riverpod
-Stream<List<PendingFriendRequestHistory>> allPendingFriendRequestHistories(
-  Ref ref,
-) {
+final allPendingFriendRequestHistoriesProvider = StreamProvider<List<PendingFriendRequestHistory>>((ref) {
   return ref.watch(pendingFriendRequestHistoryRepositoryProvider).watchAll();
-}
+});
 
 /// 监听指定 uid 的好友请求历史
-@riverpod
-Stream<List<PendingFriendRequestHistory>> pendingFriendRequestHistoriesByUid(
-  Ref ref,
-  int uid,
-) {
+final pendingFriendRequestHistoriesByUidProvider = StreamProvider.family<List<PendingFriendRequestHistory>, int>((ref, uid) {
   return ref
       .watch(pendingFriendRequestHistoryRepositoryProvider)
       .watchByUid(uid);
-}
+});

apps/im_app/lib/features/contact/di/user_request_history_provider.dart

@@ -3,9 +3,6 @@ import 'package:im_app/app/di/db_provider.dart';
 import 'package:im_app/data/repositories/user_request_history_repository_impl.dart';
 import 'package:im_app/domain/entities/user_request_history.dart';
 import 'package:im_app/domain/repositories/user_request_history_repository.dart';
-import 'package:riverpod_annotation/riverpod_annotation.dart';
-
-part 'user_request_history_provider.g.dart';
 
 // ── Repository ────────────────────────────────────────────────────────────────
 
@@ -17,22 +14,16 @@ final userRequestHistoryRepositoryProvider =
 // ── Streams ───────────────────────────────────────────────────────────────────
 
 /// 监听所有用户请求历史
-@riverpod
-Stream<List<UserRequestHistory>> allUserRequestHistories(Ref ref) {
+final allUserRequestHistoriesProvider = StreamProvider<List<UserRequestHistory>>((ref) {
   return ref.watch(userRequestHistoryRepositoryProvider).watchAll();
-}
+});
 
 /// 监听指定状态的用户请求历史
-@riverpod
-Stream<List<UserRequestHistory>> userRequestHistoriesByStatus(
-  Ref ref,
-  int status,
-) {
+final userRequestHistoriesByStatusProvider = StreamProvider.family<List<UserRequestHistory>, int>((ref, status) {
   return ref.watch(userRequestHistoryRepositoryProvider).watchByStatus(status);
-}
+});
 
 /// 监听指定用户请求历史
-@riverpod
-Stream<UserRequestHistory?> userRequestHistoryById(Ref ref, int id) {
+final userRequestHistoryByIdProvider = StreamProvider.family<UserRequestHistory?, int>((ref, id) {
   return ref.watch(userRequestHistoryRepositoryProvider).watchById(id);
-}
+});