Caddy Proxy Manager: Registrations enabled by default allows creating users with "user" permission

Caddy Proxy Manager is a web interface for managing Caddy Server reverse proxies and certificates. Prior to 1.5.1, Caddy Proxy Manager enables email and password self-registration by default at /api/auth/sign-up/email, allowing an unauthenticated remote actor to create an active account with the user role without administrator approval. The user role cannot view or modify proxy data, so the direct impact is limited to unauthorized creation of low-privilege accounts. The fixed configuration in src/lib/config.ts and src/lib/auth-server.ts requires AUTH_ALLOW_SELF_REGISTRATION=true before the authentication library's disableSignUp control permits sign-up. This issue is fixed in version 1.5.1.