The Go module name has been changed from `carrot_bbs` to `with_you`, which requires
all import paths to be updated throughout the codebase and by external consumers.
BREAKING CHANGE: Module name changed from carrot_bbs to with_you. All imports
and dependencies must be updated from carrot_bbs/* to with_you/*.
- Added WebSocket support by introducing a new WSHandler and related infrastructure.
- Replaced SSE implementations with WebSocket equivalents across message and QR code handlers.
- Updated service and repository layers to utilize WebSocket for real-time messaging.
- Removed obsolete SSE hub and related code, streamlining the application for WebSocket usage.
- Enhanced router to include WebSocket endpoints for real-time communication.
