fix: replace role check with permission check in TicketingSettingsController

isSiteAdmin() used the dropped role field. Now checks is_super_admin
or ticketing.settings permission. Closes #2.

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

src/Http/Controllers/TicketingSettingsController.php

@@ -29,8 +29,8 @@ class TicketingSettingsController extends Controller
      */
     private function isSiteAdmin(): bool
     {
-        $role = Auth::user()?->role;
-        return in_array($role, ['admin', 'super_admin']);
+        $user = Auth::user();
+        return $user && ($user->is_super_admin || $user->can('ticketing.settings'));
     }
 
     /**