- Added error handling for call invite and answer processes to differentiate between callee offline and call already answered scenarios.
- Introduced a new method to publish messages only to online users, improving real-time communication during call signaling.
- Updated call service to check callee's online status before sending call invites, ensuring better user experience.
- Enhanced call acceptance logic to notify both caller and callee about call status changes, including when a call is answered on another device.
- 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.
