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/mailer/SentMessage.php

@@ -0,0 +1,95 @@
+<?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\Mailer;
+
+use Symfony\Component\Mime\Message;
+use Symfony\Component\Mime\RawMessage;
+
+/**
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+class SentMessage
+{
+    private RawMessage $original;
+    private RawMessage $raw;
+    private string $messageId;
+    private string $debug = '';
+
+    /**
+     * @internal
+     */
+    public function __construct(
+        RawMessage $message,
+        private Envelope $envelope,
+    ) {
+        $message->ensureValidity();
+
+        $this->original = $message;
+
+        if ($message instanceof Message) {
+            $message = clone $message;
+            $headers = $message->getHeaders();
+            if (!$headers->has('Message-ID')) {
+                $headers->addIdHeader('Message-ID', $message->generateMessageId());
+            }
+            $this->messageId = $headers->get('Message-ID')->getId();
+            $this->raw = new RawMessage($message->toIterable());
+        } else {
+            $this->raw = $message;
+        }
+    }
+
+    public function getMessage(): RawMessage
+    {
+        return $this->raw;
+    }
+
+    public function getOriginalMessage(): RawMessage
+    {
+        return $this->original;
+    }
+
+    public function getEnvelope(): Envelope
+    {
+        return $this->envelope;
+    }
+
+    public function setMessageId(string $id): void
+    {
+        $this->messageId = $id;
+    }
+
+    public function getMessageId(): string
+    {
+        return $this->messageId;
+    }
+
+    public function getDebug(): string
+    {
+        return $this->debug;
+    }
+
+    public function appendDebug(string $debug): void
+    {
+        $this->debug .= $debug;
+    }
+
+    public function toString(): string
+    {
+        return $this->raw->toString();
+    }
+
+    public function toIterable(): iterable
+    {
+        return $this->raw->toIterable();
+    }
+}