Integrate OneSignal & Optimize React App

I have a React-based app that you can preview here: https://preview--game-verse-casino-hub-92645.lovable.app/. My OneSignal account is already set up; I now need the SDK wired into the app so users can opt-in and reliably receive push notifications triggered from my back-end events.

While you are inside the codebase, I’d also like you to tighten up performance—especially around data fetching. Some endpoints are called more often than necessary, and occasional delays are noticeable on slower networks. Refactoring fetch logic, introducing lightweight caching, or any other proven technique that lowers latency and reduces bundle weight is welcome.

Deliverables:
• OneSignal fully integrated with a working browser prompt and a test notification proving end-to-end delivery
• Refactored data-fetch layer with benchmarks showing faster initial load or reduced network calls
• A concise hand-off note explaining the main changes, any new environment variables, and how to extend notification logic in the future

I keep the repo on Git; you’ll receive access the moment we agree on the scope and timeline.