Fix the OpenAI API rate limit (429) error

## About the 429 error `429 Too Many Requests` is the OpenAI API telling you it's refusing a request because you've gone over a limit. It's the AI-API equivalent of any other HTTP rate-limit response — the request was well-formed, the server just won't process it right now. There are two very different causes hiding behind the same status code, and fixing the wrong one wastes time. ## Why do I see…