"Posters per row" offered 2-5 at every width, and the grid clamps a count
to what the viewport holds, so on a phone "3" and "4" still showed two.
The choices are now Auto plus every count up to what fits, capped at 5:
Auto / 1 / 2 on a 390px phone, up to 5 on a desktop. A stored preference
above the fit is shown as what is rendered and stays stored, so the
desktop keeps its choice. 1 joins the counts for the phone.
After "Show on map" isolated a zone, the only way back was re-tapping the
same legend row, inside a collapsed sheet on a phone. While a zone is
isolated (batch mode off), a chip above the map's floor names it with an
x that shows every zone again, through the wall's own deselect path
(applySelectZone(null)). Its label is the existing buttons.clearSelection.
Rebuilt: my-upg-100-list, country-posters, regions-dashboard; the tree and
SRI regenerated.