A plugin declaring the reservation-detail slot mounted at the foot of every
card in the desktop ReservationsPanel and nowhere else: the phone's transport
and booking cards never rendered the slot, so on a phone in portrait the
reservation was there and the widget was not, and turning the phone sideways
made it appear. ReservationPluginSlots mounts one PluginFrame per widget under
each card, scoped to that reservation with surface detail-slot, outside the
card's body button and gone in compact mode.
Closes#2440
214 items came out of writing the tests. Real defects are corrected, dead code
is removed rather than covered, and the tests that pinned the old behaviour
move with them.
Also drops two agent coverage scratch files that slipped into the coverage PR
and adds the ignore rule that keeps them out.
Maurice