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/event-dispatcher-contracts/Event.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\Contracts\EventDispatcher;
+
+use Psr\EventDispatcher\StoppableEventInterface;
+
+/**
+ * Event is the base class for classes containing event data.
+ *
+ * This class contains no event data. It is used by events that do not pass
+ * state information to an event handler when an event is raised.
+ *
+ * You can call the method stopPropagation() to abort the execution of
+ * further listeners in your event listener.
+ *
+ * @author Guilherme Blanco <guilhermeblanco@hotmail.com>
+ * @author Jonathan Wage <jonwage@gmail.com>
+ * @author Roman Borschel <roman@code-factory.org>
+ * @author Bernhard Schussek <bschussek@gmail.com>
+ * @author Nicolas Grekas <p@tchwork.com>
+ */
+class Event implements StoppableEventInterface
+{
+    private bool $propagationStopped = false;
+
+    public function isPropagationStopped(): bool
+    {
+        return $this->propagationStopped;
+    }
+
+    /**
+     * Stops the propagation of the event to further event listeners.
+     *
+     * If multiple event listeners are connected to the same event, no
+     * further event listener will be triggered once any trigger calls
+     * stopPropagation().
+     */
+    public function stopPropagation(): void
+    {
+        $this->propagationStopped = true;
+    }
+}