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/nesbot/carbon/src/Carbon/WeekDay.php

@@ -0,0 +1,68 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * This file is part of the Carbon package.
+ *
+ * (c) Brian Nesbitt <brian@nesbot.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Carbon;
+
+use Carbon\Exceptions\InvalidFormatException;
+
+enum WeekDay: int
+{
+    // Using constants is only safe starting from PHP 8.2
+    case Sunday = 0; // CarbonInterface::SUNDAY
+    case Monday = 1; // CarbonInterface::MONDAY
+    case Tuesday = 2; // CarbonInterface::TUESDAY
+    case Wednesday = 3; // CarbonInterface::WEDNESDAY
+    case Thursday = 4; // CarbonInterface::THURSDAY
+    case Friday = 5; // CarbonInterface::FRIDAY
+    case Saturday = 6; // CarbonInterface::SATURDAY
+
+    public static function int(self|int|null $value): ?int
+    {
+        return $value instanceof self ? $value->value : $value;
+    }
+
+    public static function fromNumber(int $number): self
+    {
+        $day = $number % CarbonInterface::DAYS_PER_WEEK;
+
+        return self::from($day + ($day < 0 ? CarbonInterface::DAYS_PER_WEEK : 0));
+    }
+
+    public static function fromName(string $name, ?string $locale = null): self
+    {
+        try {
+            return self::from(CarbonImmutable::parseFromLocale($name, $locale)->dayOfWeek);
+        } catch (InvalidFormatException $exception) {
+            // Possibly current language expect a dot after short name, but it's missing
+            if ($locale !== null && !mb_strlen($name) < 4 && !str_ends_with($name, '.')) {
+                try {
+                    return self::from(CarbonImmutable::parseFromLocale($name.'.', $locale)->dayOfWeek);
+                } catch (InvalidFormatException) {
+                    // Throw previous error
+                }
+            }
+
+            throw $exception;
+        }
+    }
+
+    public function next(?CarbonImmutable $now = null): CarbonImmutable
+    {
+        return $now?->modify($this->name) ?? new CarbonImmutable($this->name);
+    }
+
+    public function locale(string $locale, ?CarbonImmutable $now = null): CarbonImmutable
+    {
+        return $this->next($now)->locale($locale);
+    }
+}