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/mailer/Transport/AbstractTransportFactory.php

@@ -0,0 +1,47 @@
+<?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\Mailer\Transport;
+
+use Psr\EventDispatcher\EventDispatcherInterface;
+use Psr\Log\LoggerInterface;
+use Symfony\Component\Mailer\Exception\IncompleteDsnException;
+use Symfony\Contracts\HttpClient\HttpClientInterface;
+
+/**
+ * @author Konstantin Myakshin <molodchick@gmail.com>
+ */
+abstract class AbstractTransportFactory implements TransportFactoryInterface
+{
+    public function __construct(
+        protected ?EventDispatcherInterface $dispatcher = null,
+        protected ?HttpClientInterface $client = null,
+        protected ?LoggerInterface $logger = null,
+    ) {
+    }
+
+    public function supports(Dsn $dsn): bool
+    {
+        return \in_array($dsn->getScheme(), $this->getSupportedSchemes(), true);
+    }
+
+    abstract protected function getSupportedSchemes(): array;
+
+    protected function getUser(Dsn $dsn): string
+    {
+        return $dsn->getUser() ?? throw new IncompleteDsnException('User is not set.');
+    }
+
+    protected function getPassword(Dsn $dsn): string
+    {
+        return $dsn->getPassword() ?? throw new IncompleteDsnException('Password is not set.');
+    }
+}