Chrome & modern browsers block ES Modules on local file:// URLs
GeoStudio is a full Single Page Application built with modern Web APIs (ES Modules, Leaflet, Turf.js, IndexedDB, and WebGL). When opened directly from disk via file://, browsers block local script modules under their origin security policy.
python3 -m http.server 8000
Then visit http://localhost:8000 in your browser.