feat: add initial Socket.IO queue server implementation

- Created a basic Socket.IO server that manages user connections and queues for events.
- Implemented queue logic to handle concurrent user limits and JWT token issuance.
- Added MySQL configuration for potential persistence of queue positions.
- Introduced environment variables for configuration through a .env.example file.

.gitignore

@@ -31,7 +31,8 @@ yarn-error.log*
 .pnpm-debug.log*
 
 # env files (can opt-in for committing if needed)
-.env*
+.env
+.env.local
 
 # vercel
 .vercel