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/psr/log/src/NullLogger.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace Psr\Log;
+
+/**
+ * This Logger can be used to avoid conditional log calls.
+ *
+ * Logging should always be optional, and if no logger is provided to your
+ * library creating a NullLogger instance to have something to throw logs at
+ * is a good way to avoid littering your code with `if ($this->logger) { }`
+ * blocks.
+ */
+class NullLogger extends AbstractLogger
+{
+    /**
+     * Logs with an arbitrary level.
+     *
+     * @param mixed[] $context
+     *
+     * @throws \Psr\Log\InvalidArgumentException
+     */
+    public function log($level, string|\Stringable $message, array $context = []): void
+    {
+        // noop
+    }
+}