fix return data

app.py

@@ -569,8 +569,9 @@ async def stream_agent_response(question: str, chat_history: List) -> List[Dict]
             logger.error(error_msg, exc_info=True)
             assistant_message["content"] = f"## ❌ Error\n\n{error_msg}"
         
-        # Return the assistant's message
-        return [assistant_message]
+        # Return the message in the correct format for Gradio Chatbot
+        # Format: [(user_message, assistant_message)]
+        return [(None, assistant_message["content"])]
         
     except Exception as e:
         error_msg = f"## ❌ Error\n\nOcurrió un error al procesar tu solicitud:\n\n```\n{str(e)}\n```"