Alarm-Mail bei fehlgeschlagenen geplanten Aufgaben und Queue-Jobs

- OperationalAlert: Log (Kanal monitoring) immer, Mail an
  MONITORING_ALERT_EMAIL (Standard EXCEPTION_MAIL), optional ntfy;
  gleiche Meldung hoechstens einmal pro Stunde
- Kernel: onFailure fuer alle geplanten Aufgaben (auch kuenftige)
- AppServiceProvider: Queue::failing
- withoutOverlapping mit kurzen Sperrdauern (10-60 Min.) statt 24 h

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/Providers/AppServiceProvider.php

@@ -6,9 +6,12 @@ use App\Services\Backoffice\BackofficeDashboardService;
 use App\Services\Payment\Payone\PayonePaymentService;
 use App\Services\Payment\Stripe\StripeClientWrapper;
 use App\Services\Util;
+use App\Support\OperationalAlert;
 use Barryvdh\LaravelIdeHelper\IdeHelperServiceProvider;
 use Illuminate\Foundation\Console\AboutCommand;
 use Illuminate\Pagination\Paginator;
+use Illuminate\Queue\Events\JobFailed;
+use Illuminate\Support\Facades\Queue;
 use Illuminate\Support\Facades\Schema;
 use Illuminate\Support\Facades\URL;
 use Illuminate\Support\ServiceProvider;
@@ -30,6 +33,14 @@ class AppServiceProvider extends ServiceProvider
             URL::forceScheme('https');
         }
 
+        Queue::failing(function (JobFailed $event): void {
+            OperationalAlert::send('Queue-Job fehlgeschlagen: '.$event->job->resolveName(), [
+                'connection' => $event->connectionName,
+                'queue' => $event->job->getQueue(),
+                'exception' => $event->exception->getMessage(),
+            ]);
+        });
+
         AboutCommand::add('mivita', fn (): array => [
             'Version' => config('app.version') ?? 'unbekannt',
         ]);