feat(layers): GNSS interference layer from ADS-B NIC/NACp integrity

Bins airborne ADS-B v1/v2 aircraft that report degraded navigation
integrity (NIC < 7, NACp < 8, or readsb's GPS-loss flag) into 0.5 degree
cells over a rolling 30-minute window, coloured with the gpsjam.org
bands. Keyless: reads the capped adsb.lol point snapshot around the view
through /api/gnss-integrity, which returns integrity fields only, caches
60 s per whole-degree anchor, backs off on upstream 429 and serves the
last snapshot on failure. Adds scripts/qa-gnss.mjs.

Built by the Hex project (Crew Leo Agile dev team).

Co-Authored-By: Claude <[email protected]>

src/ui/layerPanel.js

@@ -49,7 +49,13 @@ const PANEL_GROUPS = [
   },
   {
     label: 'Events',
-    ids: ['rocket-launches', 'earthquakes', 'local-firms', 'fire-perimeters'],
+    ids: [
+      'rocket-launches',
+      'earthquakes',
+      'local-firms',
+      'fire-perimeters',
+      'gnss-interference',
+    ],
   },
   {
     label: 'Weather',