feat: support multiple rate limits (#11260)

Added multi-limit support end-to-end by carrying limit_name in
rate-limit snapshots and handling multiple buckets instead of only
codex.
Extended /usage client parsing to consume additional_rate_limits
Updated TUI /status and in-memory state to store/render per-limit
snapshots
Extended app-server rate-limit read response: kept rate_limits and added
rate_limits_by_name.
Adjusted usage-limit error messaging for non-default codex limit buckets

codex-rs/codex-backend-openapi-models/src/models/mod.rs

@@ -27,6 +27,9 @@ pub mod paginated_list_task_list_item_;
 pub use self::paginated_list_task_list_item_::PaginatedListTaskListItem;
 
 // Rate Limits
+pub mod additional_rate_limit_details;
+pub use self::additional_rate_limit_details::AdditionalRateLimitDetails;
+
 pub mod rate_limit_status_payload;
 pub use self::rate_limit_status_payload::PlanType;
 pub use self::rate_limit_status_payload::RateLimitStatusPayload;