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]>

server/providers/local.js

@@ -24,6 +24,7 @@ import { mapillaryProxy } from './mapillary.js';
 import { keySetupEndpoint } from '../standalone/key-setup.js';
 import { weatherProxy } from './weather.js';
 import { firePerimetersProxy } from './firePerimeters.js';
+import { gnssIntegrityProxy } from './gnssIntegrity.js';
 import { cycloneProxy } from './cyclones.js';
 import { windProxy } from './wind.js';
 
@@ -60,6 +61,7 @@ function localProviderPlugins({ realtime } = {}) {
     cycloneProxy(),
     mapillaryProxy(),
     firePerimetersProxy(),
+    gnssIntegrityProxy(),
     keySetupEndpoint(),
   ];
 }