Add status column to events table via migration and publish demo event in seeder to fix 404 errors for Guest PWA (requires published status).

database/seeders/DemoEventSeeder.php

@@ -16,6 +16,7 @@ class DemoEventSeeder extends Seeder
             'description' => ['de'=>'Demo-Event','en'=>'Demo event'],
             'date' => now()->addMonths(3)->toDateString(),
             'event_type_id' => $type->id,
+            'status' => 'published',
             'is_active' => true,
             'settings' => [],
             'default_locale' => 'de',