Introduce a new WebSocket messaging architecture that supports both standalone and cluster modes. This allows for horizontal scaling of WebSocket servers by using Redis Pub/Sub to synchronize messages across multiple instances.
Key changes:
- Added `ws.MessagePublisher` interface to abstract message distribution.
- Implemented `ws.Bus` to handle cluster-mode messaging via Redis.
- Added `ws.OnlineTracker` to manage user online status across the cluster.
- Refactored multiple services (Chat, Group, Push, Call, etc.) to use the new `MessagePublisher` instead of a concrete `ws.Hub`.
- Added WebSocket configuration options (mode, instance ID, channel, TTL, heartbeat) to `config.yaml` and `config.go`.
- Updated dependency injection with Wire to support the new publisher and Redis client.
- Improved logging by replacing standard `log` with `zap` in several service components.