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/Attribute/IsSignatureValid.php

@@ -0,0 +1,41 @@
+<?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\Attribute;
+
+/**
+ * Validates the request signature for specific HTTP methods.
+ *
+ * This class determines whether a request's signature should be validated
+ * based on the configured HTTP methods. If the request method matches one
+ * of the specified methods (or if no methods are specified), the signature
+ * is checked.
+ *
+ * If the signature is invalid, a {@see \Symfony\Component\HttpFoundation\Exception\SignedUriException}
+ * is thrown during validation.
+ *
+ * @author Santiago San Martin <sanmartindev@gmail.com>
+ */
+#[\Attribute(\Attribute::IS_REPEATABLE | \Attribute::TARGET_CLASS | \Attribute::TARGET_METHOD | \Attribute::TARGET_FUNCTION)]
+final class IsSignatureValid
+{
+    /** @var string[] */
+    public readonly array $methods;
+
+    /**
+     * @param string[]|string $methods HTTP methods that require signature validation. An empty array means that no method filtering is done
+     */
+    public function __construct(
+        array|string $methods = [],
+    ) {
+        $this->methods = (array) $methods;
+    }
+}