Monitoring (R5.3): Betriebs-Alerts fuer Scheduler-/Queue-Ausfaelle

OperationalAlert loggt critical + Best-Effort-Mail an MONITORING_ALERT_EMAIL
(Fallback LEGAL_CONTACT_EMAIL, feature-flagged). Alle 6 Scheduler-Tasks mit
onFailure, Queue::failing-Listener; .env.example: LOG_STACK=daily als Prod-Soll.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/Providers/AppServiceProvider.php

@@ -23,6 +23,7 @@ use App\Observers\AdminPerformanceCacheObserver;
 use App\Services\Admin\AdminRequestPerformanceMetrics;
 use App\Services\Newsletter\NullNewsletterSyncClient;
 use App\Services\PressRelease\PressReleaseService;
+use App\Support\OperationalAlert;
 use Illuminate\Auth\Events\Login;
 use Illuminate\Auth\Events\Registered;
 use Illuminate\Auth\Events\Verified;
@@ -31,9 +32,11 @@ use Illuminate\Auth\Notifications\ResetPassword;
 use Illuminate\Auth\Notifications\VerifyEmail;
 use Illuminate\Database\Events\QueryExecuted;
 use Illuminate\Notifications\Messages\MailMessage;
+use Illuminate\Queue\Events\JobFailed;
 use Illuminate\Support\Facades\DB;
 use Illuminate\Support\Facades\Event;
 use Illuminate\Support\Facades\Gate;
+use Illuminate\Support\Facades\Queue;
 use Illuminate\Support\Facades\URL;
 use Illuminate\Support\ServiceProvider;
 use Laravel\Cashier\Cashier;
@@ -91,6 +94,17 @@ class AppServiceProvider extends ServiceProvider
         Gate::define('access-admin', fn (User $user): bool => $user->canAccessAdmin());
         Gate::define('access-customer', fn (User $user): bool => $user->canAccessCustomer());
 
+        // Betriebs-Alert bei fehlgeschlagenem Queue-Job (R5.3): die KI-Jobs
+        // laufen auf der `classification`-Queue — ein stiller Stau in
+        // `failed_jobs` würde jede Einreichung in der Prüfung hängen lassen.
+        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(),
+            ]);
+        });
+
         // Registrierung → Verifizierungsmail; bestätigter Klick → Aktivierung.
         Event::listen(Registered::class, SendEmailVerificationNotification::class);
         Event::listen(Verified::class, ActivateUserAfterVerification::class);