- Reworked the tenant admin login page

- Updated the User model to implement Filament’s tenancy contracts
- Seeded a ready-to-use demo tenant (user, tenant, active package, purchase)
- Introduced a branded, translated 403 error page to replace the generic forbidden message for unauthorised admin hits
- Removed the public “Register” links from the marketing header
- hardened join event logic and improved error handling in the guest pwa.

database/seeders/DemoEventSeeder.php

@@ -20,7 +20,7 @@ class DemoEventSeeder extends Seeder
             'description' => ['de'=>'Demo-Event','en'=>'Demo event'],
             'date' => now()->addMonths(3)->toDateString(),
             'event_type_id' => $type->id,
-            'status' => 'active',
+            'status' => 'published',
             'is_active' => true,
             'settings' => json_encode([]),
             'default_locale' => 'de',