mat-sz/filedrop — reverse-engineered prompt

Build me a clean web app for private file sharing between two people. I want someone to open the site, create or join a drop, and send files directly to the other person in the browser when possible. It should use WebRTC for direct transfer and a small server for pairing or signaling. Everything should be end to end encrypted, including file names, basic metadata, and the small chat messages between the two users.

Keep the interface really minimal, mobile friendly, and easy for non technical people. Show a clear connection state, file transfer progress, success or failure messages, and a simple chat box that supports copy and paste. Make it installable as a Progressive Web App so it feels like a small phone app too.

Please set up both the React front end and the Node server, with sensible local dev and production run instructions. Look up current docs online if needed.