zxcodes/Shopzy — reverse-engineered prompt

Build me a polished mobile shopping app called Shopzy that feels modern and easy to use on both iPhone and Android. I want a nice home screen with product cards, a product details screen, a favorites screen, and a cart screen, similar to a real store app. Users should be able to browse items, tap into a product to see more info, save things they like, and add or remove items from the cart. Keep the cart and favorites updated everywhere in the app so it feels smooth and consistent.

Please use React Native with TypeScript and make it run cleanly in Expo. If there is no real backend, just use sensible sample product data and focus on the user experience and clean state handling. Make the UI look attractive, with good spacing, images, prices, and simple interactions. Set it up so I can run it easily on a simulator or in Expo Go. If anything is unclear, look up the current Expo docs online and make the best practical version.