fix(installations): send an identifying User-Agent to Overpass (#570)

Supersedes #420 by @GladiatorrX9, 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: Cyber Knight <[email protected]>

server/providers/overpass/constants.js

@@ -3,6 +3,19 @@ import path from 'node:path';
 // ---------------------------------------------------------------------------
 // Overpass API proxy constants and cache state
 // ---------------------------------------------------------------------------
+/**
+ * User-Agent sent to every Overpass mirror.
+ *
+ * The OSM API usage policy asks for a "Valid User-Agent identifying application
+ * and version"; a generic proxy label is not one. A mirror is free to refuse a
+ * client it cannot identify, and `src/overpassProxy.test.mjs` pins what that
+ * costs: a refusal is never data, so the query falls through to whatever
+ * mirrors are left. Keep this honest and stable — if it is ever refused, the
+ * answer is less query volume, not a new name.
+ */
+const OVERPASS_USER_AGENT =
+  'gods-eye-view/0.1 (+https://github.com/bilawalsidhu/gods-eye-view)';
+
 /** Ordered list of Overpass API mirrors; tried sequentially on failure/rate-limit. */
 const OVERPASS_UPSTREAMS = [
   'https://overpass-api.de/api/interpreter',
@@ -130,5 +143,6 @@ export {
   OVERPASS_SIMPLIFY_TOLERANCE_DEG,
   OVERPASS_MAX_RESPONSE_BYTES,
   OVERPASS_UPSTREAMS,
+  OVERPASS_USER_AGENT,
   OVERPASS_TIMEOUT_MS,
 };