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/mime/Encoder/Rfc2231Encoder.php

@@ -0,0 +1,50 @@
+<?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\Mime\Encoder;
+
+use Symfony\Component\Mime\CharacterStream;
+
+/**
+ * @author Chris Corbyn
+ */
+final class Rfc2231Encoder implements EncoderInterface
+{
+    /**
+     * Takes an unencoded string and produces a string encoded according to RFC 2231 from it.
+     */
+    public function encodeString(string $string, ?string $charset = 'utf-8', int $firstLineOffset = 0, int $maxLineLength = 0): string
+    {
+        $lines = [];
+        $lineCount = 0;
+        $lines[] = '';
+        $currentLine = &$lines[$lineCount++];
+
+        if (0 >= $maxLineLength) {
+            $maxLineLength = 75;
+        }
+
+        $charStream = new CharacterStream($string, $charset);
+        $thisLineLength = $maxLineLength - $firstLineOffset;
+
+        while (null !== $char = $charStream->read(4)) {
+            $encodedChar = rawurlencode($char);
+            if ('' !== $currentLine && \strlen($currentLine.$encodedChar) > $thisLineLength) {
+                $lines[] = '';
+                $currentLine = &$lines[$lineCount++];
+                $thisLineLength = $maxLineLength;
+            }
+            $currentLine .= $encodedChar;
+        }
+
+        return implode("\r\n", $lines);
+    }
+}