所有数据库表，提供相应的provider、桥接等方法

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

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+import 'package:flutter_riverpod/flutter_riverpod.dart';
+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 ────────────────────────────────────────────────────────────────
+
+/// 消息仓储 Provider
+final messageRepositoryProvider = Provider<MessageRepository>((ref) {
+  return MessageRepositoryImpl(ref.watch(storageSdkProvider));
+});
+
+// ── Streams ───────────────────────────────────────────────────────────────────
+
+/// 监听指定 chatId 的消息列表
+@riverpod
+Stream<List<Message>> messagesByChatId(Ref ref, int chatId) {
+  return ref.watch(messageRepositoryProvider).watchByChatId(chatId);
+}
+
+/// 监听指定消息
+@riverpod
+Stream<Message?> messageById(Ref ref, int id) {
+  return ref.watch(messageRepositoryProvider).watchById(id);
+}