Build Local Grocery Delivery App

I need a complete mobile application that lets neighbourhood shoppers order groceries from my store in much the same way they would on Jio Mart or Big Basket. The project must cover both iOS and Android so a single-code-base framework such as Flutter or React Native is fine, but I am open to native builds if you prefer.

Core user-facing flow
• New users create an account or sign in quickly with email, phone or social login.
• Shoppers browse our product catalogue, run keyword searches, filter by category and see real-time pricing and availability.
• A smooth cart and checkout experience lets them place an order, choose delivery or pick-up, and pay online (UPI, cards, wallets).
• After checkout, in-app order tracking shows each stage from “packed” to “out for delivery” with push notifications.

I have no fixed deadline, so you can schedule milestones sensibly around design, development, testing and app-store submission. Please include the full source code, short technical documentation, and a brief hand-over call so my team can maintain the app after launch.