Fix VWORLD boundary API: correct dataset name, attrFilter encoding, and response path

- Fix dataset name LT_C_ADSSIGG_INFO → LT_C_ADSIGG_INFO (double S typo)
- Fix attrFilter: remove encodeURIComponent (caused double-encoding) and % wildcards
- Fix extractFeatures: add featureCollection.features path (VWORLD response structure)
- Fix Overpass relationToGeoJSON: assemble way segments into complete rings
- Add assembleRings with endpoint matching and area-based filtering
- Add VWORLD API key UI with localStorage persistence
- Add VWORHD tile layer with OSM fallback
- Add VWORLD geocode with Nominatim fallback

server.py

@@ -5,5 +5,5 @@ PORT = 8000
 Handler = http.server.SimpleHTTPRequestHandler
 
 with socketserver.TCPServer(("", PORT), Handler) as httpd:
-    print(f"Serving at http://localhost:{PORT}")
+    print(f"Serving at http://0.0.0.0:{PORT}")
     httpd.serve_forever()