feat(search): Nominatim as the last-resort geocoder (#573)

Supersedes #350 by @sendmebits, ported onto the current component layout with fixes from review.

Verified before merge: format, package boundaries, unit suite, build, and the browser tracking suite; a browser harness for the change where one applies; adversarial review applied.

Co-authored-by: sendmebits <[email protected]>

server/providers/local.js

@@ -7,6 +7,7 @@ import { adsbdbProxy } from './aircraft/enrichment.js';
 import { overpassProxy } from './overpass.js';
 import { militaryInstallationsProxy } from './military-installations.js';
 import { regionalBriefProxy } from './regional/briefing.js';
+import { geocodeProxy } from './regional/place.js';
 import { weatherEffectsProxy } from './regional/weather-effects.js';
 import { cctvProxy } from './cctv.js';
 import { defaultSourceRoot } from './common/source-root.js';
@@ -32,6 +33,7 @@ function localProviderPlugins() {
     overpassProxy(),
     militaryInstallationsProxy(),
     regionalBriefProxy(),
+    geocodeProxy(),
     weatherEffectsProxy(),
     cctvProxy({ sourceRoot: defaultSourceRoot }),
     radioBrowserProxy(),