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/Controller/ArgumentResolver/DefaultValueResolver.php

@@ -0,0 +1,37 @@
+<?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\Controller\ArgumentResolver;
+
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpKernel\Controller\ValueResolverInterface;
+use Symfony\Component\HttpKernel\ControllerMetadata\ArgumentMetadata;
+
+/**
+ * Yields the default value defined in the action signature when no value has been given.
+ *
+ * @author Iltar van der Berg <kjarli@gmail.com>
+ */
+final class DefaultValueResolver implements ValueResolverInterface
+{
+    public function resolve(Request $request, ArgumentMetadata $argument): array
+    {
+        if ($argument->hasDefaultValue()) {
+            return [$argument->getDefaultValue()];
+        }
+
+        if (null !== $argument->getType() && $argument->isNullable() && !$argument->isVariadic()) {
+            return [null];
+        }
+
+        return [];
+    }
+}