arya2004/paytm-hackathon ? reverse-engineered prompt

Build me a proof of concept for delegated payments that feels like a simple Paytm style demo.

I want a small system with a shared backend, a browser extension, a merchant checkout page, and a mobile friendly app. The flow should let a user register a demo identity, save a VPA and PIN, redeem a few fake gift cards, and then pay from a merchant page by clicking Pay with Paytm. For payments, give two options, instant gift card success or a delegated UPI style approval that gets sent to the phone app for approve or reject. Keep everything fake, no real payment APIs.

Please make the demo easy to run locally, use a single public backend URL for all the clients, and store demo state so balances, gift cards, delegate requests, and transactions persist. If you need current setup details, look up the latest docs online. I’d also like a small terminal demo for a food ordering style flow if that fits naturally.