I think what I'd like is this: On the Raspberry Pi 4 I got as a present from an old friend who doesn't need it anymore, I have a music server running. But when I'm asleep, it doesn't need to run so I'd like to pull the cable but I'm also afraid of corrupting the filesystem. So ideally there'd be a super tiny web server-like app running (20 lines of Go?) that would do nothing but serve a HTML button. If you click it, it runs "sudo shutdown now".