Swiss AI Hub v0.303.1

Changed

• 📄 Clarified Superuser Account Configuration: The platform's superuser account now consistently uses
  SUPERUSER_EMAIL as its Keycloak username, aligning with Keycloak's registrationEmailAsUsername enforcement for
  login. The SUPERUSER_USERNAME variable has been re-designated as a log-only label for internal tracking, removing
  its previous role in setting the Keycloak username. This update simplifies superuser provisioning and enhances clarity
  in documentation across deployment guides and access control sections.