Apple Music disappeared from Apple Watch 10.6.1

Today I noticed that Apple Music has disappeared from my Apple Watch. I hadn't uninstalled anything. attempts to re-install from App Store fail. tells me "requires iPhone" in the app store (and I have an iPhone connected to the watch). when I go to my iPhone, I don't see any opportunity to install on watch. I don't see it in the watch app on my iPhone.

the watch and iPhone are connected via bluetooth

it is a cellular watch

this has been working fine for a number of years now. until today.