feat(smtp): add a precious SMTP test for admin only

static/locales/en.json

@@ -649,7 +649,23 @@
         "migration_verify_passed": "Verification passed",
         "migration_verify_failed": "Verification failed",
         "migration_failed_blobs": "failed blobs",
-        "testing": "Testing…"
+        "testing": "Testing…",
+        "tab_smtp": "SMTP",
+        "smtp_title": "Outbound Email (SMTP)",
+        "smtp_intro": "SMTP is configured exclusively via environment variables (OXICLOUD_SMTP_*). The values below are read from the running server — to change them, edit the environment and restart OxiCloud.",
+        "smtp_enabled_label": "Status",
+        "smtp_enabled": "Enabled",
+        "smtp_disabled": "Disabled (host unset)",
+        "smtp_test_title": "Send a test email",
+        "smtp_test_intro": "Sends a hardcoded diagnostic message to the recipient below and reports the SMTP server's response so you can correlate it with your relay logs.",
+        "smtp_test_to": "Recipient address",
+        "smtp_send_test": "Send test email",
+        "smtp_sending": "Sending…",
+        "smtp_sent": "Test email sent.",
+        "smtp_send_failed": "Send failed.",
+        "smtp_server_code": "Server replied",
+        "smtp_test_missing_to": "Enter a recipient address.",
+        "smtp_not_configured": "SMTP is not configured on this server."
     },
     "profile": {
         "page_title": "Profile",

static/locales/fr.json

@@ -649,7 +649,23 @@
         "migration_verify_passed": "Vérification réussie",
         "migration_verify_failed": "Échec de la vérification",
         "migration_failed_blobs": "Blobs échoués",
-        "testing": "Test en cours..."
+        "testing": "Test en cours...",
+        "tab_smtp": "SMTP",
+        "smtp_title": "E-mail sortant (SMTP)",
+        "smtp_intro": "Le SMTP est configuré exclusivement via les variables d'environnement (OXICLOUD_SMTP_*). Les valeurs ci-dessous proviennent du serveur en cours d'exécution — pour les modifier, éditez l'environnement et redémarrez OxiCloud.",
+        "smtp_enabled_label": "État",
+        "smtp_enabled": "Activé",
+        "smtp_disabled": "Désactivé (hôte non défini)",
+        "smtp_test_title": "Envoyer un e-mail de test",
+        "smtp_test_intro": "Envoie un message de diagnostic au destinataire ci-dessous et affiche la réponse du serveur SMTP afin que vous puissiez la corréler avec les journaux de votre relais.",
+        "smtp_test_to": "Adresse du destinataire",
+        "smtp_send_test": "Envoyer l'e-mail de test",
+        "smtp_sending": "Envoi…",
+        "smtp_sent": "E-mail de test envoyé.",
+        "smtp_send_failed": "Échec de l'envoi.",
+        "smtp_server_code": "Le serveur a répondu",
+        "smtp_test_missing_to": "Veuillez saisir une adresse de destinataire.",
+        "smtp_not_configured": "Le SMTP n'est pas configuré sur ce serveur."
     },
     "profile": {
         "page_title": "Profil",