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>

config/services.php

@@ -0,0 +1,38 @@
+<?php
+
+return [
+
+    /*
+    |--------------------------------------------------------------------------
+    | Third Party Services
+    |--------------------------------------------------------------------------
+    |
+    | This file is for storing the credentials for third party services such
+    | as Mailgun, Postmark, AWS and more. This file provides the de facto
+    | location for this type of information, allowing packages to have
+    | a conventional file to locate the various service credentials.
+    |
+    */
+
+    'postmark' => [
+        'key' => env('POSTMARK_API_KEY'),
+    ],
+
+    'resend' => [
+        'key' => env('RESEND_API_KEY'),
+    ],
+
+    'ses' => [
+        'key' => env('AWS_ACCESS_KEY_ID'),
+        'secret' => env('AWS_SECRET_ACCESS_KEY'),
+        'region' => env('AWS_DEFAULT_REGION', 'us-east-1'),
+    ],
+
+    'slack' => [
+        'notifications' => [
+            'bot_user_oauth_token' => env('SLACK_BOT_USER_OAUTH_TOKEN'),
+            'channel' => env('SLACK_BOT_USER_DEFAULT_CHANNEL'),
+        ],
+    ],
+
+];