feat: 支持 agent 运行取消功能

apps/lib/features/chat/data/services/ag_ui_service.dart

@@ -50,6 +50,8 @@ class AgUiService {
   Completer<void>? _activeSseDoneCompleter;
 
   String? _threadId;
+  String? _activeThreadIdForRun;
+  String? _activeRunId;
   bool _hasMoreHistory = false;
 
   AgUiService({EventCallback? onEvent, required IApiClient apiClient})
@@ -83,11 +85,20 @@ class AgUiService {
       throw StateError('Missing runId in /agent/runs response');
     }
     _threadId = threadId;
-    await _streamEventsFromApi(
-      threadId,
-      expectedRunId: runId,
-      streamToken: streamToken,
-    );
+    _activeThreadIdForRun = threadId;
+    _activeRunId = runId;
+    try {
+      await _streamEventsFromApi(
+        threadId,
+        expectedRunId: runId,
+        streamToken: streamToken,
+      );
+    } finally {
+      if (_activeThreadIdForRun == threadId && _activeRunId == runId) {
+        _activeThreadIdForRun = null;
+        _activeRunId = null;
+      }
+    }
     return SendMessageResult(
       uploadedAttachments: runInputPayload.uploadedAttachments,
     );
@@ -151,6 +162,19 @@ class AgUiService {
   }
 
   Future<void> cancelCurrentRun() async {
+    final activeThreadId = _activeThreadIdForRun;
+    final activeRunId = _activeRunId;
+    if (activeThreadId != null && activeRunId != null) {
+      final encodedRunId = Uri.encodeQueryComponent(activeRunId);
+      await _apiClient.post<Map<String, dynamic>>(
+        '/api/v1/agent/runs/$activeThreadId/cancel?runId=$encodedRunId',
+      );
+      _activeThreadIdForRun = null;
+      _activeRunId = null;
+      _activeStreamToken += 1;
+      await _cancelActiveSseSubscription();
+      return;
+    }
     _activeStreamToken += 1;
     await _cancelActiveSseSubscription();
   }

apps/lib/features/chat/presentation/bloc/chat_bloc.dart

@@ -123,10 +123,16 @@ class ChatBloc extends Cubit<ChatState> {
         );
       case AgUiEventType.runError:
         final errorEvent = event as RunErrorEvent;
+        final isCanceledByUser = errorEvent.code == 'RUN_CANCELED';
         emit(
           _resetRunState(
-            error: errorEvent.message,
-          ).copyWith(items: _markActiveToolCallsFailed(state.items)),
+            error: isCanceledByUser ? null : errorEvent.message,
+          ).copyWith(
+            items: _markActiveToolCallsFailed(
+              state.items,
+              reason: isCanceledByUser ? '本次运行已取消' : '本次运行已失败',
+            ),
+          ),
         );
       case AgUiEventType.stepStarted:
         _handleStepStarted(event as StepStartedEvent);
@@ -286,7 +292,10 @@ class ChatBloc extends Cubit<ChatState> {
     return items.where((item) => item is! ToolCallItem).toList();
   }
 
-  List<ChatListItem> _markActiveToolCallsFailed(List<ChatListItem> items) {
+  List<ChatListItem> _markActiveToolCallsFailed(
+    List<ChatListItem> items, {
+    required String reason,
+  }) {
     return items.map((item) {
       if (item is! ToolCallItem) {
         return item;
@@ -297,10 +306,7 @@ class ChatBloc extends Cubit<ChatState> {
       if (item.status == ToolCallStatus.completed) {
         return item;
       }
-      return item.copyWith(
-        status: ToolCallStatus.error,
-        errorMessage: '本次运行已失败',
-      );
+      return item.copyWith(status: ToolCallStatus.error, errorMessage: reason);
     }).toList();
   }
 

apps/lib/features/home/ui/screens/home_screen_interactions.dart

@@ -75,7 +75,7 @@ extension _HomeScreenInteractions on _HomeScreenState {
       return;
     }
     if (canceled) {
-      Toast.show(context, '已停止等待回复', type: ToastType.info);
+      Toast.show(context, '已请求停止', type: ToastType.info);
     }
   }