Fix parameter name: user_input -> user_message

app.py

@@ -79,7 +79,7 @@ async def chat_endpoint(character_id: str, request: Request):
         # Get response from character using generate_response method
         response = character_manager.generate_response(
             character_id=character_id,
-            user_input=message,
+            user_message=message,
             conversation_history=history
         )