refactor: add error message in response object

app.py

@@ -85,7 +85,8 @@ async def upload(
                 logging.info("File uploaded successfully")
 
             except Exception as e:
-                logging.warning(f"Error during upload: {e}")
+                res = str(e)
+                logging.warning(f"Error during upload: {res}")
                 return {"error": "Failed to upload content"}
     
     return {"result": res}