Feature-Rich Website-to-App Conversion

I have a fully functioning website and now need it turned into a mobile app that feels native while still relying on my existing back-end. Users must sign in with the same credentials they already use on the site, so the current authentication flow (session / token based) has to be integrated directly. Core functionality I’m after: the app should load the site’s content in a mobile-friendly wrapper, then layer in push notifications and location-based features (maps, nearby results, geofencing—whatever fits best). I will supply the API endpoints for login, content retrieval, and notification tokens; you handle the mobile implementation, UI refinements, and submission to both the App Store and Google Play. Deliverables • Single codebase (Flutter, React Native, or similar) compiled for iOS & Android • Seamless website login using existing user accounts • Push notification set-up (Firebase or comparable) tested end-to-end • Location & map integration with permission handling and graceful fallback • Store-ready builds plus clear setup/build instructions Please include examples of apps where you added both push notifications and geolocation, and outline your preferred tech stack so I can move quickly on approvals.