The macOS play/pause key goes to the wrong app, so I built a router for it

A YouTube tab is playing in Brave. I press play/pause on the keyboard. The video keeps going and Apple Music opens on top of everything, playing a song I did not ask for. I did this for years. Close Music, click the tab, press space. Then one evening I opened Console to find out why, and ended up writing SmartPause, a small menu bar app that sends...