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/CacheClearer/Psr6CacheClearer.php

@@ -0,0 +1,66 @@
+<?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\CacheClearer;
+
+use Psr\Cache\CacheItemPoolInterface;
+
+/**
+ * @author Nicolas Grekas <p@tchwork.com>
+ */
+class Psr6CacheClearer implements CacheClearerInterface
+{
+    private array $pools = [];
+
+    /**
+     * @param array<string, CacheItemPoolInterface> $pools
+     */
+    public function __construct(array $pools = [])
+    {
+        $this->pools = $pools;
+    }
+
+    public function hasPool(string $name): bool
+    {
+        return isset($this->pools[$name]);
+    }
+
+    /**
+     * @throws \InvalidArgumentException If the cache pool with the given name does not exist
+     */
+    public function getPool(string $name): CacheItemPoolInterface
+    {
+        if (!$this->hasPool($name)) {
+            throw new \InvalidArgumentException(\sprintf('Cache pool not found: "%s".', $name));
+        }
+
+        return $this->pools[$name];
+    }
+
+    /**
+     * @throws \InvalidArgumentException If the cache pool with the given name does not exist
+     */
+    public function clearPool(string $name): bool
+    {
+        if (!isset($this->pools[$name])) {
+            throw new \InvalidArgumentException(\sprintf('Cache pool not found: "%s".', $name));
+        }
+
+        return $this->pools[$name]->clear();
+    }
+
+    public function clear(string $cacheDir): void
+    {
+        foreach ($this->pools as $pool) {
+            $pool->clear();
+        }
+    }
+}