akbarsheikh-debug/wondersnap ? reverse-engineered prompt

Build me a browser app that lets people control glowing 3D models with hand gestures from a webcam. I want it to run locally with a simple Node server, open in Chrome or Edge, and work even without a camera by using on screen controls and keyboard shortcuts.

The main experience should be a bunch of particles that snap into different models like famous landmarks, body parts, engines, and vehicles. People should be able to make a fist to form a model, open their hand to switch or explode it apart, point to select a piece, pinch to pull a part closer, and use two hands to zoom. It should also support labels, a helpful info card for selected parts, a quiz mode, voice commands, and a demo mode.

Make it feel polished and interactive, with smooth motion, a start screen, camera permissions handling, and good fallback behavior if the webcam is unavailable. If you need current docs for camera or gesture APIs, look them up online.