重构架构：恢复统一的 llm_call 节点，移除错误的 final_response 节点

backend/app/main_graph/utils/main_graph_builder.py

@@ -10,11 +10,11 @@ from app.main_graph.state import MainGraphState, CurrentAction
 from app.main_graph.nodes.react_nodes import (
     init_state_node,
     react_reason_node,
-    web_search_node,  # ⭐ 新增
+    web_search_node,
     error_handling_node,
-    final_response_node,
     route_by_reasoning
 )
+from app.main_graph.nodes.llm_call import create_llm_call_node
 from app.main_graph.nodes.rag_nodes import rag_retrieve_node
 from app.subgraphs.contact import build_contact_subgraph
 from app.subgraphs.dictionary import build_dictionary_subgraph
@@ -75,10 +75,10 @@ def wrap_subgraph_for_error_handling(subgraph, name: str):
 
 
 # ========== 主图构建 ==========
-def build_react_main_graph() -> StateGraph:
+def build_react_main_graph(llm=None, tools=None) -> StateGraph:
     """
     构建完整的 React 模式主图
-    
+
     流程：
     START
       ↓
@@ -87,18 +87,23 @@ def build_react_main_graph() -> StateGraph:
     react_reason (推理) ←──────────────┐
       ↓                                │
     条件路由                          │
-      ├─→ rag_retrieve →───────────────┤
-      ├─→ contact_subgraph →───────────┤
-      ├─→ dictionary_subgraph →────────┤
-      ├─→ news_analysis_subgraph →─────┤
-      ├─→ handle_error → (重试或结束) ──┤
-      └─→ final_response
+      ├─ rag_retrieve →───────────────┤
+      ├─ contact_subgraph →───────────┤
+      ├─ dictionary_subgraph →────────┤
+      ├─ news_analysis_subgraph →─────┤
+      ├─ handle_error → (重试或结束) ─┤
+      └─ llm_call → END
       ↓
     END
     """
     # 创建图
     graph = StateGraph(MainGraphState)
     
+    # 创建 llm_call 节点
+    llm_node = None
+    if llm is not None:
+        llm_node = create_llm_call_node(llm, tools or [])
+    
     # ========== 添加节点 ==========
     
     # 1. 初始化节点
@@ -110,14 +115,15 @@ def build_react_main_graph() -> StateGraph:
     # 3. RAG 检索节点
     graph.add_node("rag_retrieve", rag_retrieve_node)
     
-    # 4. 联网搜索节点 ⭐ 新增
+    # 4. 联网搜索节点
     graph.add_node("web_search", web_search_node)
     
     # 5. 错误处理节点
     graph.add_node("handle_error", error_handling_node)
     
-    # 6. 最终回答节点
-    graph.add_node("final_response", final_response_node)
+    # 6. LLM 调用节点（真正的大模型输出）
+    if llm_node is not None:
+        graph.add_node("llm_call", llm_node)
     
     # ========== 添加子图节点 ==========
     
@@ -154,33 +160,34 @@ def build_react_main_graph() -> StateGraph:
         {
             # 检索分支 → 检索后回到推理
             "rag_retrieve": "rag_retrieve",
-            
-            # 联网搜索分支 ⭐ 新增
+
+            # 联网搜索分支
             "web_search": "web_search",
-            
+
             # 子图分支 → 子图后回到推理
             "contact_subgraph": "contact_subgraph",
             "dictionary_subgraph": "dictionary_subgraph",
             "news_analysis_subgraph": "news_analysis_subgraph",
-            
+
             # 错误处理分支
             "handle_error": "handle_error",
-            
-            # 最终回答分支
-            "final_response": "final_response",
+
+            # LLM 调用分支 → 直接输出给用户
+            "llm_call": "llm_call"
         }
     )
-    
-    # 4. 循环边：检索/搜索/子图/错误处理 后 → 回到推理
+
+    # 4. 循环边：检索/搜索/子图/错误处理后 → 回到推理
     graph.add_edge("rag_retrieve", "react_reason")
-    graph.add_edge("web_search", "react_reason")  # ⭐ 新增
+    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")  # 错误处理后可能重试
-    
-    # 5. 最终边：final_response → END
-    graph.add_edge("final_response", END)
+    graph.add_edge("handle_error", "react_reason")
+
+    # 5. 最终边：llm_call → END
+    if llm_node is not None:
+        graph.add_edge("llm_call", END)
     
     return graph