Cloudflare Zones

Every domain the grant covers, so the operator can pick one.

Unselectable zones are returned but flagged rather than hidden — an operator whose zone is still pending should see why it is not selectable, not wonder where their domain went.

selectable means exactly "/custom-domain/deploy will accept this". The two must agree: offering a domain the deploy route then refuses is how an operator ends up clicking Publish to find out. Each zone therefore carries the deploy route's own reason for refusing it.