The backups <details> carried hx-preserve="true" to survive the card's
30s poll without collapsing if the operator had it open -- but hx-preserve
freezes the whole node, so "newest X ago" inside it never updated either,
same class of bug as the Started column before it got its own JS-side
toggle state. Drop hx-preserve; track open/closed the same way (stable id,
state re-applied after every swap) so the count/age text stays live.
Simone
9ab760a64c