Landlords can now remove a tenant from their room via a "Mieter
ausziehen lassen" button on the contract card. This never deletes
anything: POST /contracts/:id/move-out sets Contract.isActive=false
(with an endDate), frees the room (User.roomId=null,
Room.status=VACANT) so it can be re-assigned via the existing invite
flow, and leaves the contract row — along with every linked payment,
ticket, rating, handover protocol, and contract document — untouched
and permanently queryable.
GET /contracts/documents now only lists active contracts; the new
GET /contracts/archive (landlord/admin only) lists deactivated ones,
rendered in a new "Archiv — ausgezogene Mieter" section on the
Verträge-page with their historical documents still downloadable.