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-foundation/Session/Flash/FlashBagInterface.php

@@ -0,0 +1,72 @@
+<?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\HttpFoundation\Session\Flash;
+
+use Symfony\Component\HttpFoundation\Session\SessionBagInterface;
+
+/**
+ * FlashBagInterface.
+ *
+ * @author Drak <drak@zikula.org>
+ */
+interface FlashBagInterface extends SessionBagInterface
+{
+    /**
+     * Adds a flash message for the given type.
+     */
+    public function add(string $type, mixed $message): void;
+
+    /**
+     * Registers one or more messages for a given type.
+     */
+    public function set(string $type, string|array $messages): void;
+
+    /**
+     * Gets flash messages for a given type.
+     *
+     * @param string $type    Message category type
+     * @param array  $default Default value if $type does not exist
+     */
+    public function peek(string $type, array $default = []): array;
+
+    /**
+     * Gets all flash messages.
+     */
+    public function peekAll(): array;
+
+    /**
+     * Gets and clears flash from the stack.
+     *
+     * @param array $default Default value if $type does not exist
+     */
+    public function get(string $type, array $default = []): array;
+
+    /**
+     * Gets and clears flashes from the stack.
+     */
+    public function all(): array;
+
+    /**
+     * Sets all flash messages.
+     */
+    public function setAll(array $messages): void;
+
+    /**
+     * Has flash messages for a given type?
+     */
+    public function has(string $type): bool;
+
+    /**
+     * Returns a list of all defined types.
+     */
+    public function keys(): array;
+}