Gate payment gateway behind Pro and Business plans.

Free accounts keep cash sales only; connecting a gateway and card/MoMo
checkout require a paid plan, with settings upsell copy for free users.

app/Http/Controllers/Pos/SettingsController.php

@@ -53,6 +53,7 @@ class SettingsController extends Controller
             'tables' => $this->scopeToLocation($request, PosTable::owned($owner))
                 ->orderBy('area')->orderBy('position')->orderBy('label')->get(),
             'gateway' => $this->gateway->settingFor($account),
+            'canUsePaymentGateway' => $this->subscriptions->canUsePaymentGateway($account),
         ]);
     }
 
@@ -144,6 +145,7 @@ class SettingsController extends Controller
     /**
      * Upsert merchant gateway credentials for the acting account.
      * Blank secret fields keep the previously stored encrypted values.
+     * Free plan cannot connect or change gateway credentials.
      */
     protected function persistGateway(Request $request, User $user): void
     {
@@ -160,6 +162,11 @@ class SettingsController extends Controller
             return;
         }
 
+        if (! $this->subscriptions->canUsePaymentGateway($user)) {
+            // Ignore gateway fields on free plan (other settings may still save).
+            return;
+        }
+
         $attributes = [
             'provider' => $provider !== '' ? $provider : $existing->provider,
             'is_active' => $request->boolean('gateway_is_active'),