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/Loader/JsonFileLoader.php

@@ -0,0 +1,51 @@
+<?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\Loader;
+
+use Symfony\Component\Translation\Exception\InvalidResourceException;
+
+/**
+ * JsonFileLoader loads translations from an json file.
+ *
+ * @author singles
+ */
+class JsonFileLoader extends FileLoader
+{
+    protected function loadResource(string $resource): array
+    {
+        $messages = [];
+        if ($data = file_get_contents($resource)) {
+            $messages = json_decode($data, true);
+
+            if (0 < $errorCode = json_last_error()) {
+                throw new InvalidResourceException('Error parsing JSON: '.$this->getJSONErrorMessage($errorCode));
+            }
+        }
+
+        return $messages;
+    }
+
+    /**
+     * Translates JSON_ERROR_* constant into meaningful message.
+     */
+    private function getJSONErrorMessage(int $errorCode): string
+    {
+        return match ($errorCode) {
+            \JSON_ERROR_DEPTH => 'Maximum stack depth exceeded',
+            \JSON_ERROR_STATE_MISMATCH => 'Underflow or the modes mismatch',
+            \JSON_ERROR_CTRL_CHAR => 'Unexpected control character found',
+            \JSON_ERROR_SYNTAX => 'Syntax error, malformed JSON',
+            \JSON_ERROR_UTF8 => 'Malformed UTF-8 characters, possibly incorrectly encoded',
+            default => 'Unknown error',
+        };
+    }
+}