feat(websocket): integrate WebSocket support and refactor SSE handling

- 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.

go.sum

@@ -124,6 +124,8 @@ github.com/google/wire v0.7.0 h1:JxUKI6+CVBgCO2WToKy/nQk0sS+amI9z9EjVmdaocj4=
 github.com/google/wire v0.7.0/go.mod h1:n6YbUQD9cPKTnHXEBN2DXlOp/mVADhVErcMFb0v3J18=
 github.com/gorilla/securecookie v1.1.1/go.mod h1:ra0sb63/xPlUeL+yeDciTfxMRAA+MP+HVt/4epWDjd4=
 github.com/gorilla/sessions v1.2.1/go.mod h1:dk2InVEVJ0sfLlnXv9EAgkf6ecYs/i80K/zI+bUmuGM=
+github.com/gorilla/websocket v1.5.3 h1:saDtZ6Pbx/0u+bgYQ3q96pZgCzfhKXGPqt7kZ72aNNg=
+github.com/gorilla/websocket v1.5.3/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
 github.com/hashicorp/go-uuid v1.0.2/go.mod h1:6SBZvOh/SIDV7/2o3Jml5SYk/TvGqwFJ/bN7x4byOro=
 github.com/hashicorp/go-uuid v1.0.3/go.mod h1:6SBZvOh/SIDV7/2o3Jml5SYk/TvGqwFJ/bN7x4byOro=
 github.com/hashicorp/golang-lru/v2 v2.0.7 h1:a+bsQ5rvGLjzHuww6tVxozPZFVghXaHOwFs4luLUK2k=