feat: add real-time collaboration features with STOMP and SockJS

- Added @stomp/stompjs and sockjs-client dependencies for WebSocket communication.
- Updated routing for pastes to include new endpoint structure.
- Implemented real-time editing in PastePanel using STOMP for collaborative editing.
- Introduced NotificationModal for experimental mode warnings.
- Enhanced NavBar to display connection status.
- Refactored Home and PastePanel components to support new features and improve user experience.
- Updated error handling in DataContext to utilize ErrorContext for better error management.
- Added CSS animations for connection status indication.

public/config/settings.prod.json

@@ -4,8 +4,8 @@
     "endpoints": {
       "pastes": {
         "all": "/pastes",
-        "byId": "/:pasteId",
-        "byKey": "/:pasteKey"
+        "byId": "/by-id/:pasteId",
+        "byKey": "/s/:pasteKey"
       }
     }
   }