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/var-dumper/Caster/ProxyManagerCaster.php

@@ -0,0 +1,35 @@
+<?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\VarDumper\Caster;
+
+use ProxyManager\Proxy\ProxyInterface;
+use Symfony\Component\VarDumper\Cloner\Stub;
+
+/**
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @final
+ *
+ * @internal since Symfony 7.3
+ */
+class ProxyManagerCaster
+{
+    public static function castProxy(ProxyInterface $c, array $a, Stub $stub, bool $isNested): array
+    {
+        if ($parent = get_parent_class($c)) {
+            $stub->class .= ' - '.$parent;
+        }
+        $stub->class .= '@proxy';
+
+        return $a;
+    }
+}