Add bulk lifecycle actions to the bookings tab (confirm, complete, cancel, release, mark unused, delete)

Add a "Checkin" tab on the slot entity for door staff to admit bookings without the camera, as the manual fallback to the QR camera kiosk.

Provide a filter by order (type or pick the order number) that lists that order's bookings on the slot as rows, each with a check-in button, plus a batch "check in selected" action so a whole order can be admitted at once. It reuses the existing check-in handler: each booking already resolves to its compact handle, so this needs no new identity. See the compact check-in handle work in #3613083.