Evict a defaulting tenant: delinquent -> vacated (M5.19).

Until now delinquent was a state with no way out. The machine defined ("delinquent", "admin_close") -> vacated and nothing called it — there was no admin route for booking state at all. Meanwhile delinquent is in _BILLABLE, so the ticker kept minting monthly cycles for a tenant who had stopped paying, and it is in BLOCKING_STATES, so the unit stayed off the market for ever. _terminate_ended could not help either: it only matches notice_given and active.

Deliberately admin-only and deliberately narrow. Closing a booking releases a unit somebody may still have possessions in, so it is an operator decision with a real-world step attached, not something to automate on a timer.