Rocktopus101/Hingemonium ? reverse-engineered prompt

Build me a fun macOS app that turns a MacBook into a playable harmonium.

I want to press the bottom rows of the keyboard to play notes, with a clear on screen guide showing which key maps to which note. The laptop lid should act like the bellows, so opening and closing it pumps air, and the faster I move the lid the louder the notes get. If I stop moving the lid, the sound should fade out naturally.

Please include a simple way to switch between a few musical scales like chromatic, major, and minor, so it’s easier to play melodies. Use harmonium style sounds, and make the app feel polished and playful.

If you need to, look up any current macOS docs or APIs online while building it. I’d also like it to be something I can open in Xcode and run on a MacBook without a bunch of setup.