API Mode (not leaving the page)
For SPAs and fetch() calls - shows auth in an iframe overlay:
Browser Mode (full page)
Block access to otherwise open site - intended for forward-auth mechanism (Caddy, Nginx). If not authenticated, you'll see the login page; after auth, a 204 response (blank page = success). Back returns here:
🔐 Basic Auth 🔄 Reauth (max_age=10s) 🛡️ Admin OnlyClick a button to test...