fix: workflow onEndWithStream handles stream asynchronously (#518)

backend/domain/workflow/internal/execute/callback.go

@@ -496,7 +496,7 @@ func (w *WorkflowHandler) OnEndWithStreamOutput(ctx context.Context, info *callb
 		return ctx
 	}
 
-	// consumes the stream synchronously because the Exit node has already processed this stream synchronously.
+	safego.Go(ctx, func() {
 		defer output.Close()
 		fullOutput := make(map[string]any)
 		for {
@@ -512,12 +512,12 @@ func (w *WorkflowHandler) OnEndWithStreamOutput(ctx context.Context, info *callb
 
 				logs.Errorf("workflow OnEndWithStreamOutput failed to receive stream output: %v", e)
 				_ = w.OnError(ctx, info, e)
-			return ctx
+				return
 			}
 			fullOutput, e = nodes.ConcatTwoMaps(fullOutput, chunk.(map[string]any))
 			if e != nil {
 				logs.Errorf("failed to concat two maps: %v", e)
-			return ctx
+				return
 			}
 		}
 
@@ -538,6 +538,7 @@ func (w *WorkflowHandler) OnEndWithStreamOutput(ctx context.Context, info *callb
 			}
 		}
 		w.ch <- e
+	})
 
 	return ctx
 }