The prefix location /cd/dashboard proxied requests without a trailing
slash directly to Tommy CD, so the browser resolved relative CSS/JS
assets against /cd/ instead of /cd/dashboard/, breaking the styling.

Redirect the exact /cd/dashboard path to /cd/dashboard/ first, same
pattern already used for /cd and /cd/.

Refs T2289

Verified the location block logic mirrors the existing /cd and /cd/
redirect pattern already deployed for this vhost. Manual check on
web-001 recommended once deployed: hit https://infra.nasqueron.org/cd/dashboard
without a trailing slash and confirm CSS loads.