- golem15.users.manage_backend_links (no default role), en and pl labels
- record actions on summercms.cabana.users: link_frontend_account asks for
the frontend user's email (exact, case-insensitive, active users only),
records linked_by and fires the link events; unlink_frontend_account
(danger) removes the link
- a taken or unknown account answers 422 on the prompt
- permissions (the four Winter codes and manage_privileged_groups),
the user navigation item and the embedded admin YAML
- Users controller: list with deactivated users, row states, the
groups, created date and activated filters, and the form's name,
surname and email
- a member of a group in golem15.user.privileged_groups (default
admin) keeps their email, password and row unless the administrator
holds golem15.users.manage_privileged_groups; the refusal is a 403
that saves nothing
