- Introduced `publishErrorEvent` in `Manager` to publish error events to Redis.
- Implemented error event structure to capture authentication errors with detailed metadata.
- Added test cases for error event publishing, subscription, and Redis protocol handling.
- Enhanced error and usage queue handling with `SubscribeErrors` and `EnqueueError`.
Closes: #3701
- Introduced `NotifyUsageRefresh` in `redisqueue` to notify subscribers of usage refresh events.
- Enhanced `Watcher` logic to trigger usage refresh notifications on client changes (add/update/remove).
- Updated tests to validate proper broadcast of usage refresh messages to subscribers.
- Added support for initial `support_refresh` payload upon subscription initialization.
- Added Redis Pub/Sub capability to broadcast usage updates to subscribed clients.
- Enhanced `redisqueue` with subscriber management and message broadcasting.
- Updated tests to validate Pub/Sub message handling, subscription behavior, and fallback to the queue after unsubscribing.
- Integrated `project_id` parsing into auth-files logic to include project identifiers in metadata.
- Introduced `redis-usage-queue-retention-seconds` config parameter with a default of 60 seconds and a max of 3600 seconds.
- Updated logic in `redisqueue` to honor configurable retention periods for enqueued usage data.
- Modified config validation and initialization to support and enforce retention limits.
- Enhanced change tracking in `config_diff` to detect updates to this parameter.
- Added `protocol_multiplexer.go`, enabling support for both HTTP and Redis protocols on a single listener.
- Introduced `redis_queue_protocol.go` to handle Redis-compatible RESP commands for queue management.
- Integrated `redisqueue` package, supporting in-memory queuing with expiration pruning.
- Updated server initialization to manage a shared listener and multiplex connections.
- Adjusted `Handler` to adopt `AuthenticateManagementKey` for modular key validation, supporting both HTTP and Redis flows.
