- controller golem15.user.usergroups behind golem15.users.access_groups
- list with users_count from the list's own query; form with the checkbox
permission editor stored in user_groups.permissions
- creating a group with a privileged code, changing a code to or from one and
deleting a privileged group need golem15.users.manage_privileged_groups
- a group delete removes its users_groups rows in the same transaction
- UserGroup gains Fillable, Rules and the read-only UsersCount; PermissionSet.Text
- TestAdminGroups and the D-06 matrix in TestAdminPrivilegedGroups
- 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
