OSM tile.openstreetmap.org was returning grey tiles on the portal (likely rate-limiting the Cloudflare tunnel egress IP). Switch to CARTO Voyager tiles which are free, CDN-backed, and don't have the same restrictions. Also add data-tile-subdomains attribute support in history.js so tile provider subdomains can be configured per-deployment. Co-authored-by: Copilot <[email protected]>