修复三个问题：1. 子图执行后的无限循环 2. llm_call没有输出 3. 思考打印两次

- 子图执行后直接进入finalize，避免回到react_reason循环
- llm_call节点检查是否已有final_result，避免重复调用LLM
- 直接在react_reason_node中通过adispatch_custom_event发送推理事件，避免通过state传递导致重复

backend/app/main_graph/utils/main_graph_builder.py

@@ -61,15 +61,34 @@ def wrap_subgraph_for_error_handling(subgraph, name: str):
             result = subgraph.invoke(state)
             
             # 更新主图状态
+            subgraph_result = None
             if name == "contact":
                 state.contact_result = result
+                subgraph_result = result.get("final_result", "")
             elif name == "dictionary":
                 state.dictionary_result = result
+                subgraph_result = result.get("final_result", "")
             elif name == "news_analysis":
                 state.news_result = result
+                subgraph_result = result.get("final_result", "")
+            
+            # 关键：设置最终结果，这样就不需要再回到 react_reason 了
+            if subgraph_result:
+                state.final_result = subgraph_result
+            else:
+                state.final_result = "子图执行完成"
             
             # 标记成功
             state.success = True
+            state.current_phase = "done"
+            # 标记不再需要推理，避免循环
+            state.reasoning_history.append({
+                "step": state.reasoning_step,
+                "action": "subgraph_completed",
+                "confidence": 1.0,
+                "reasoning": f"{name}子图执行完成",
+                "timestamp": datetime.now().isoformat()
+            })
             return state
             
         except Exception as e:
@@ -189,18 +208,18 @@ def build_react_main_graph(llm=None, tools=None, mem0_client=None) -> StateGraph
     graph.add_node("finalize", finalize_node)
     
     # ========== 添加边 ==========
-    
+
     # 第一阶段：记忆检索
     if retrieve_memory_node:
         graph.add_edge(START, "retrieve_memory")
         graph.add_edge("retrieve_memory", "memory_trigger")
     else:
         graph.add_edge(START, "memory_trigger")
-    
+
     # 进入第二阶段
     graph.add_edge("memory_trigger", "init_state")
     graph.add_edge("init_state", "react_reason")
-    
+
     # 第二阶段：React 循环推理
     graph.add_conditional_edges(
         "react_reason",
@@ -215,15 +234,17 @@ def build_react_main_graph(llm=None, tools=None, mem0_client=None) -> StateGraph
             "llm_call": "llm_call"
         }
     )
-    
-    # 循环边
+
+    # 循环边（rag、web_search、error 回到 reason）
     graph.add_edge("rag_retrieve", "react_reason")
     graph.add_edge("web_search", "react_reason")
-    graph.add_edge("contact_subgraph", "react_reason")
-    graph.add_edge("dictionary_subgraph", "react_reason")
-    graph.add_edge("news_analysis_subgraph", "react_reason")
     graph.add_edge("handle_error", "react_reason")
     
+    # 关键修改：子图执行完后直接去 finalize（避免循环）
+    graph.add_edge("contact_subgraph", "finalize")
+    graph.add_edge("dictionary_subgraph", "finalize")
+    graph.add_edge("news_analysis_subgraph", "finalize")
+    
     # 第三阶段：llm_call 后进入完成处理
     if llm_node is not None:
         if summarize_node: