Band toggles previously roundtripped through LiveView and rebuilt every
polyline + popup + hover handler on each click. Now the hook builds one
L.LayerGroup per band once after the initial fetch; toggling is just
addLayer/removeLayer on the map (O(bands), not O(contacts)). Checkbox
and All/None events are handled directly in the hook via delegated
document listeners — no LV roundtrip. Callsign filter still roundtrips
(debounced) since it's cross-cutting, and now iterates pre-built
polylines without recreating them.
Graham McIntire
6972feb2c2