NegiCoder/MeshPay ? reverse-engineered prompt

Build me a demo app for offline UPI payments that feels like a live network console.

I want a simple dashboard where I can pick a sender, receiver, and amount, then click a button to encrypt the payment, pass it through a few simulated nearby phones, and finally upload it when one of them gets internet. Show the whole flow in a visual way, with counters for settled, dropped, invalid, and rejected payments, plus live balances for a few demo users.

The important part is that the same payment can arrive more than once, but it should only settle once. Please make it protect against tampering and old replayed packets too. It should work locally without extra services, and also be easy to run with Docker for a more realistic setup. If you need to look up current docs online while building it, go ahead.