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-php85/bootstrap.php

@@ -0,0 +1,32 @@
+<?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\Php85 as p;
+
+if (\PHP_VERSION_ID >= 80500) {
+    return;
+}
+
+if (!function_exists('get_error_handler')) {
+    function get_error_handler(): ?callable { return p\Php85::get_error_handler(); }
+}
+
+if (!function_exists('get_exception_handler')) {
+    function get_exception_handler(): ?callable { return p\Php85::get_exception_handler(); }
+}
+
+if (!function_exists('array_first')) {
+    function array_first(array $array) { return p\Php85::array_first($array); }
+}
+
+if (!function_exists('array_last')) {
+    function array_last(array $array) { return p\Php85::array_last($array); }
+}