gprem09/air-pen ? reverse-engineered prompt

Build me a simple browser app that lets me draw on a wall with my finger using a webcam and a projector.

The idea is that the webcam tracks my index finger in real time, then the page draws a glowing line wherever my finger moves. I want to open it in the browser, allow camera access, and then cast or share that tab to a projector so the wall becomes the canvas. Keep it easy to run locally.

I’d like the controls to be simple, hold Shift to draw, press Space to clear the screen, and press F to toggle fullscreen. Make the drawing feel smooth and responsive, and make sure the projector side does not need any special setup, it should just show whatever the browser is drawing. If you need current setup details, look up the latest docs online.