bashalarmistalt/decimen-optical-transfer ? reverse-engineered prompt

Build me a browser based file transfer app that sends a file from one device to another using only a screen and a camera.

I want one page for sending and one page for receiving. The sender should turn the file into an endless animated stream of QR codes, and the receiver should open the camera, scan the codes, and rebuild the file on the other device. It should work with no network connection between the devices, no pairing, and no extra app. If the receiver joins in late, it should still be able to lock onto the stream and finish the transfer. Please verify the final file with a hash and show a clear completion state and progress while it runs.

Make it easy to try locally in the browser, including the camera permission flow, and use HTTPS for the dev server since the camera needs a secure context. Add simple settings on both sides for things like transfer size, speed, and camera quality, and keep the whole thing feeling like a clean proof of concept.