Destructures `remaining` and `resetAt` from `checkRateLimit` and adds standard rate-limiting headers (`Retry-After`, `X-RateLimit-Limit`, `X-RateLimit-Remaining`) to the 429 Too Many Requests response.
Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>