fix(app): fix instance chat routing to iAgent instead of OpenClaw

chatRepositoryProvider and sendMessageUseCaseProvider were not overridden
in AgentInstanceChatPage's ProviderScope, causing ChatNotifier.sendMessage
to use the parent scope's ChatRemoteDatasource (iAgent endpoint
POST /api/v1/agent/tasks) instead of AgentInstanceChatDatasource
(OpenClaw endpoint POST /api/v1/agent/instances/:id/tasks).

Fix: override both providers in the child scope so the full call chain
(sendMessage → SendMessage → ChatRepositoryImpl → createTask) routes
to the correct instance-specific endpoint.

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

it0_app/lib/features/agent_instance_chat/presentation/pages/agent_instance_chat_page.dart

@@ -1,10 +1,16 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
+import '../../../auth/data/providers/auth_provider.dart';
+import '../../../chat/data/datasources/chat_local_datasource.dart';
+import '../../../chat/data/models/chat_message_model.dart';
+import '../../../chat/data/repositories/chat_repository_impl.dart';
+import '../../../chat/domain/usecases/send_message.dart';
 import '../../../chat/presentation/pages/chat_page.dart';
 import '../../../chat/presentation/providers/chat_providers.dart';
 import '../../../my_agents/presentation/pages/my_agents_page.dart';
 import '../../data/datasources/agent_instance_chat_remote_datasource.dart';
 import '../../../../core/network/dio_client.dart';
+import '../../../../core/network/websocket_client.dart';
 import '../../../../core/widgets/floating_robot_fab.dart';
 import '../../../../core/widgets/robot_painter.dart';
 
@@ -29,6 +35,28 @@ class AgentInstanceChatPage extends StatelessWidget {
           return AgentInstanceChatDatasource(dio, instance.id);
         }),
 
+        // chatRepositoryProvider must also be overridden so that sendMessage
+        // goes through AgentInstanceChatDatasource (instance endpoint) rather
+        // than the parent scope's ChatRemoteDatasource (iAgent endpoint).
+        chatRepositoryProvider.overrideWith((ref) {
+          final remote = ref.watch(chatRemoteDatasourceProvider);
+          final local = ref.watch(chatLocalDatasourceProvider);
+          final ws = ref.watch(webSocketClientProvider);
+          final storage = ref.watch(secureStorageProvider);
+          return ChatRepositoryImpl(
+            remoteDatasource: remote,
+            localDatasource: local ?? _NoOpLocal(),
+            webSocketClient: ws,
+            getAccessToken: () => storage.read(key: 'access_token'),
+          );
+        }),
+
+        // sendMessageUseCaseProvider must be overridden so ChatNotifier.sendMessage
+        // reads the child-scope chatRepositoryProvider (instance endpoint).
+        sendMessageUseCaseProvider.overrideWith(
+          (ref) => SendMessage(ref.watch(chatRepositoryProvider)),
+        ),
+
         // Fresh, isolated chatProvider for this instance — does NOT share
         // state with iAgent's chatProvider in the parent scope.
         chatProvider.overrideWith((ref) => ChatNotifier(ref)),
@@ -58,3 +86,15 @@ class AgentInstanceChatPage extends StatelessWidget {
     );
   }
 }
+
+/// No-op local cache — instance chat sessions are not cached locally.
+class _NoOpLocal implements ChatLocalDatasource {
+  @override
+  Future<void> cacheMessages(String sessionId, List<ChatMessageModel> messages) async {}
+  @override
+  List<ChatMessageModel> getCachedMessages(String sessionId) => [];
+  @override
+  Future<void> clearCache(String sessionId) async {}
+  @override
+  Future<void> clearAllCaches() async {}
+}