The previous wrapper gated /admin/* on a /auth/session check and only showed
the panel when an admin session was detected. Two failures:
1. The session check effect depended on `isAdminRoute` (a boolean), so the
client-side login → dashboard navigation (both /admin/*) never re-ran it.
hasAdminSession stayed stale-false from the logged-out /admin/login render,
so a freshly logged-in admin landed on the maintenance screen anyway.
2. It also hid /admin/login itself (the catch-22).
Fix: the maintenance screen only blocks customer/gallery/public routes —
/admin/* is never blocked. The admin auth layer already handles access
(AdminLayout redirects a logged-out admin to /admin/login), so no session
probe is needed here. Removes the fragile /auth/session dependency entirely.
Backend skipPaths (/api/auth/admin/login + /api/auth/session) stays: login and
AdminAuthContext's token validation must still work during maintenance.