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/polyfill-intl-normalizer/bootstrap.php

@@ -0,0 +1,23 @@
+<?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.
+ */
+
+use Symfony\Polyfill\Intl\Normalizer as p;
+
+if (\PHP_VERSION_ID >= 80000) {
+    return require __DIR__.'/bootstrap80.php';
+}
+
+if (!function_exists('normalizer_is_normalized')) {
+    function normalizer_is_normalized($string, $form = p\Normalizer::FORM_C) { return p\Normalizer::isNormalized($string, $form); }
+}
+if (!function_exists('normalizer_normalize')) {
+    function normalizer_normalize($string, $form = p\Normalizer::FORM_C) { return p\Normalizer::normalize($string, $form); }
+}