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/symfony/http-kernel/TerminableInterface.php

@@ -0,0 +1,32 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpKernel;
+
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+
+/**
+ * Terminable extends the Kernel request/response cycle with dispatching a post
+ * response event after sending the response and before shutting down the kernel.
+ *
+ * @author Jordi Boggiano <j.boggiano@seld.be>
+ * @author Pierre Minnieur <pierre.minnieur@sensiolabs.de>
+ */
+interface TerminableInterface
+{
+    /**
+     * Terminates a request/response cycle.
+     *
+     * Should be called after sending the response and before shutting down the kernel.
+     */
+    public function terminate(Request $request, Response $response): void;
+}