## What changed
- Accept optional `account/rateLimits/read` capabilities for Luna Reserve support
and lightweight background polling while preserving omitted and `null` params.
- Forward the Luna Reserve capability only for eligible ChatGPT sessions, and let
lightweight polls skip the separate reset-credit detail request.
- Return the backend's `ordinaryUsageAllowed` decision only when its account and
user identity match the active session.
## Testing
- Cover capability defaults, eligible and restricted authentication modes,
lightweight polling, identity filtering, and backend permission handling.
GitOrigin-RevId: f407a3ae1e70e411fdf245f072a16e453f59cd87