- RoleAdminController.createRole: default null description to "" and null scope to "custom"
- RoleAdminController.updateRole: pass null audit details to avoid NPE when name is null
- GroupAdminController.updateGroup: pass null audit details to avoid NPE when name is null
- UserAdminController: add POST / createUser endpoint with default VIEWER role assignment
- UserAdminController: add PUT /{userId} updateUser endpoint for displayName/email updates