fix(middleware): sync raw tool call metadata (#2757)

backend/packages/harness/deerflow/agents/middlewares/subagent_limit_middleware.py

@@ -7,6 +7,7 @@ from langchain.agents import AgentState
 from langchain.agents.middleware import AgentMiddleware
 from langgraph.runtime import Runtime
 
+from deerflow.agents.middlewares.tool_call_metadata import clone_ai_message_with_tool_calls
 from deerflow.subagents.executor import MAX_CONCURRENT_SUBAGENTS
 
 logger = logging.getLogger(__name__)
@@ -63,7 +64,7 @@ class SubagentLimitMiddleware(AgentMiddleware[AgentState]):
         logger.warning(f"Truncated {dropped_count} excess task tool call(s) from model response (limit: {self.max_concurrent})")
 
         # Replace the AIMessage with truncated tool_calls (same id triggers replacement)
-        updated_msg = last_msg.model_copy(update={"tool_calls": truncated_tool_calls})
+        updated_msg = clone_ai_message_with_tool_calls(last_msg, truncated_tool_calls)
         return {"messages": [updated_msg]}
 
     @override