Backstage <= 1.4.2 - Unauthenticated Privilege Escalation via Permissive Demo Role Capabilities

The Backstage - Customizer Demo Access plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 1.4.2. This is due to the plugin assigning the `manage_options` capability to the `backstage_customizer_user` demo role, which is more permissive than necessary for Customizer-only demo access. This makes it possible for unauthenticated attackers to navigate beyond the Customizer and update arbitrary WordPress options such as `default_role`, leading to privilege escalation.