Caddy SORTS top-level directives, so a 'rewrite' runs before 'basicauth'.
The rewrite changed /admin/ to /admin.html, and the path-based auth matchers
then saw /admin.html (which matched the family 'not path /admin/*' block, not
the operator '/admin/*' block) — so the operator password was checked against
the family hash and 401'd.
Serve each page from its own 'handle' block (which preserves order, so the
auth is checked on the original path before any file rewrite):
- handle /admin* : operator (frank) only, try_files /admin.html
- handle @data : shared data + assets, family (dank) OR operator (frank), so
the admin page's fetches of services.json/status.json reuse the operator
credential
- handle : everything else (the user page), family (dank)