docs: CCTV panel collapse on switch-off, and changelog fragment

docs/CURRENT-STATE.md

@@ -2229,6 +2229,11 @@ shown without a fade once it is decoded (or after one second if its decode never
 settles), so a new camera's preview is blank only while its frame loads. Disposal
 releases listeners, subscriptions, image handlers, summary timers and chip-hide timers.
 
+The panel opens when a camera becomes active and collapses when the layer is
+switched off, from its own switch or anywhere else; a context-mode layer clear
+keeps it as it is. A panel opened by hand while the layer is off stays open,
+and its meta line reads the catalog count, not the last active camera.
+
 ## UI disposal
 
 UI disposal releases the CCTV subscription, command-dock observer, legacy drag