A WordPress administrator previously inherited the studio-admin
capabilities but not `manage_availability`, so the studio owner running
as an admin had no way to reach "My Availability" or act as the
instructor — breaking single-instructor businesses.
Grant the instructor capabilities to administrators as well (via the
existing `user_has_cap` filter), and make both grants — studio-admin and
instructor — independently toggleable from a new Access admin page.
- RoleManager: extract `INSTRUCTOR_CAPS`; apply studio and instructor
cap sets to administrators, each gated on a stored toggle (default on).
- AccessSettings + templates/admin/access.php: two options
(`us_admin_grant_studio` / `us_admin_grant_instructor`), gated on the
core `manage_options` capability so disabling a grant can never lock an
administrator out of re-enabling it.
- AdminMenu: register the Access page after Studio Settings; keep the
studio sidebar separator visible for any administrator.
- Tests for the toggles and the new settings reader; docs updated.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
