test(agent-chat): audit guardrail and error handling

backend/src/agent/run.py

@@ -9,9 +9,10 @@
 #            when GRADIO_ALLOW_PORT_FALLBACK=true and an external proxy is updated separately.
 # @REJECTED Hardcoding the port was rejected — it must be configurable for different deployment environments.
 import socket
+
 import httpx
 
-from src.agent._config import FASTAPI_URL, SERVICE_JWT, GRADIO_SERVER_NAME, GRADIO_SERVER_PORT, GRADIO_ALLOW_PORT_FALLBACK
+from src.agent._config import FASTAPI_URL, GRADIO_ALLOW_PORT_FALLBACK, GRADIO_SERVER_NAME, GRADIO_SERVER_PORT, SERVICE_JWT
 from src.core.cot_logger import seed_trace_id
 from src.core.logger import logger
 
@@ -80,6 +81,7 @@ def _fetch_llm_config() -> dict | None:
 
 if __name__ == "__main__":
     import asyncio
+
     from src.agent.app import create_chat_interface
     from src.agent.context import set_service_jwt
     from src.agent.langgraph_setup import configure_from_api, init_checkpointer