Master's b2369bc fixed cameras vanishing after opening a popup and zooming:
Leaflet 1.9.4's Map.closePopup() never nulls map._popup, so the old
'if (map._popup) return' guard skipped every overlay reload forever after
the first popup. Port the fix into the redesigned frontend: track popup
state via popupopen/popupclose, close on user zoom/drag so moveend reloads
always run, and keep the autopan skip for the popup's own pan.