Loads the built embed/fasm-embed.js directly (not via a dev server). Build
first: npm run build-embed. Serve over HTTP, not file:// — the
tile/AGOL fetches get CORS-blocked otherwise, e.g. npx serve . from the repo
root, then open http://localhost:3000/embed-test.html. Non-interactive
preview — click the map to open the full site at this location/zoom/language. See also
embed-test-multi.html for independent multiple instances on one page.