[Hardening] F-02: Default Configuration Forces User’s Posture to Password-Only.

### The required feature described as a wish

**Description:** the global configuration setting `enable.user.2fa` defaults to False, meaning users who wish to use two-factor authentication (2FA) cannot do so without a Root Admin first enabling the setting and restarting the management server(s).

**Affected Components:** Management UI

**Impact:** Any compromised or weak user credential is sufficient to gain full access to a user's CloudStack account. This makes the platform susceptible to credential-stuffing, phishing, and brute-force attacks with no second factor to impede unauthorized access.

**Steps to Reproduce:**
- Log in to the CloudStack Management UI as a Root Admin.
- Navigate to Configuration > Global Settings.
- Search for `enable.user.2fa` and observe that its value is set to False.
- Attempt to enable 2FA on your own user account, and confirm that it is not permitted.

**Recommended Remediation:** Change the default value of `enable.user.2fa` to True so that users are always permitted to enroll in 2FA without requiring Root Admin intervention.

Commencez par le traitement de enable.user.2fa dans la Management UI, au niveau de Global Settings, et vérifiez comment sa valeur par défaut contrôle l’inscription des utilisateurs. La modification est terminée lorsque la valeur par défaut permet aux utilisateurs de s’inscrire à 2FA sans intervention d’un Root Admin ni redémarrage du management-server ; confirmez le paramètre et le flux d’inscription dans l’UI.

Rédigé par le modèle d'indexation à partir du texte de l'issue.