修复子图中 state 的导入路径

backend/app/subgraphs/contact/graph.py

@@ -6,7 +6,7 @@ Contact Subgraph Builder
 
 from app.main_graph.graph import StateGraph, START, END
 
-from app.main_graph.state import ContactState
+from .state import ContactState
 from .nodes import create_contact_nodes
 
 

backend/app/subgraphs/contact/nodes.py

@@ -10,7 +10,7 @@ from datetime import datetime
 # 公共工具
 from ..common import MarkdownFormatter
 
-from app.main_graph.state import ContactState, ContactAction, Contact, Email
+from .state import ContactState
 from .api_client import ContactAPIClient