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/translation/Provider/ProviderInterface.php

@@ -0,0 +1,30 @@
+<?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\Translation\Provider;
+
+use Symfony\Component\Translation\TranslatorBag;
+use Symfony\Component\Translation\TranslatorBagInterface;
+
+interface ProviderInterface extends \Stringable
+{
+    /**
+     * Translations available in the TranslatorBag only must be created.
+     * Translations available in both the TranslatorBag and on the provider
+     * must be overwritten.
+     * Translations available on the provider only must be kept.
+     */
+    public function write(TranslatorBagInterface $translatorBag): void;
+
+    public function read(array $domains, array $locales): TranslatorBag;
+
+    public function delete(TranslatorBagInterface $translatorBag): void;
+}