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/Exception/ResolverNotFoundException.php

@@ -0,0 +1,33 @@
+<?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\Exception;
+
+class ResolverNotFoundException extends \RuntimeException
+{
+    /**
+     * @param string[] $alternatives
+     */
+    public function __construct(string $name, array $alternatives = [])
+    {
+        $msg = \sprintf('You have requested a non-existent resolver "%s".', $name);
+        if ($alternatives) {
+            if (1 === \count($alternatives)) {
+                $msg .= ' Did you mean this: "';
+            } else {
+                $msg .= ' Did you mean one of these: "';
+            }
+            $msg .= implode('", "', $alternatives).'"?';
+        }
+
+        parent::__construct($msg);
+    }
+}