geekksv/ShareNow ? reverse-engineered prompt

Build me a browser app for sending files directly from one device to another, without uploading the file to a server or storing it anywhere.

I want two people to pair either with a short 6 digit code or a shareable link, then the file should stream from one browser straight to the other. Please make it work on desktop and mobile, with a clean interface that shows progress, whether the connection is direct or relayed, and what happens if the transfer is paused, cancelled, or drops out. It should be able to resume after a reconnect or even after reloading the page, and it should verify the file at the end so the receiver knows it arrived unchanged.

Also add QR code sharing, a native share option where supported, and warnings before refreshing or closing the tab during an active transfer. I’d like the backend just to handle pairing and connection setup, not file data. If you need to look up current browser docs or best practices, go ahead.