iOS & Android E-Commerce App

I already run the online store https://naysan.store and now I want a fully-featured mobile experience on both iOS and Android. The goal is not just to wrap the site in a WebView, but to build a smooth, app-native storefront that lets customers browse products, add them to cart, check out securely, track orders, and receive timely updates.

Core functions I need:
• Full e-commerce flow tied to my existing catalogue, inventory, and order system
• Integrated payments through Credit/Debit card and PayPal at checkout
• Push notifications for promotions, order status, and other user updates

If you favour Flutter, React Native, Swift/Kotlin, or another modern framework, let me know—performance and maintainability matter more to me than the specific stack. I already handle the web back-end, so you can consume existing APIs or help refine them for mobile where necessary.

Deliverables:
1. Production-ready iOS and Android builds, prepared for App Store and Play Store submission
2. Source code with clear documentation and instruction for future maintenance
3. A brief hand-off session so I can test, sign, and publish confidently

Please outline your proposed tech stack, timeline, and any similar apps you have launched. I’m ready to move quickly once we agree on the approach.