Stand: SMTP-Test, Admin-Mail-Tab, Notifiable-Fix, Lazy-Quill

- Fix: Notifiable-Trait zum User-Model hinzugefuegt (behebt notify()-500er)
- Installer: SMTP-Verbindungstest mit EsmtpTransport + Ueberspringen-Link
- Admin: Neuer E-Mail-Tab mit SMTP-Konfiguration + Verbindungstest
- Admin: Lazy Quill-Initialisierung (nur sichtbare Locale wird geladen)
- Uebersetzungen: 17 neue Mail-Keys in allen 6 Sprachen

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

vendor/laravel/sail/stubs/rabbitmq.stub

@@ -0,0 +1,20 @@
+rabbitmq:
+    image: 'rabbitmq:4-management-alpine'
+    hostname: 'rabbitmq'
+    ports:
+        - '${FORWARD_RABBITMQ_PORT:-5672}:5672'
+        - '${FORWARD_RABBITMQ_DASHBOARD_PORT:-15672}:15672'
+    environment:
+        RABBITMQ_HOST: "%"
+        RABBITMQ_USER: '${RABBITMQ_USER}'
+        RABBITMQ_PASSWORD: '${RABBITMQ_PASSWORD}'
+        RABBITMQ_VHOST: '${RABBITMQ_VHOST}'
+        RABBITMQ_QUEUE: '${RABBITMQ_QUEUE}'
+    volumes:
+        - 'sail-rabbitmq:/var/lib/rabbitmq'
+    networks:
+        - sail
+    healthcheck:
+        test: ["CMD", "rabbitmq-diagnostics", "-q", "ping"]
+        retries: 3
+        timeout: 5s