Tell an ex-follower they are one: Reject(Follow) on removal
Removing a follower was silent, so the other side kept us in its books
as a live relationship while nothing was ever delivered again — the hub
sat there 'following' dev.klonkt.com for days. Reject(Follow) is the
standard signal for exactly this, and the removal itself never waits on
it: the row is gone first, the notice is a courtesy that may fail.
Blocking already carries the stronger Block signal, so this covers the
other door: the owner removing someone by hand.
Co-Authored-By: Claude Fable 5 <noreply@…>