Stop Paystack pre-modal flash on customer checkout.

Use the shared Inline sheet, hold busy until payment UI opens, and avoid locking page scroll during the handoff.

resources/js/app.js

@@ -183,6 +183,8 @@ Alpine.data('miniPaymentLanding', (config = {}) => ({
     errorMsg: config.errorMsg ?? '',
     showSheet: false,
     checkoutUrl: '',
+    accessCode: '',
+    returnUrl: '',
     paymentSheetStyle: '',
     sheetBleedStyle: '',
 
@@ -259,9 +261,10 @@ Alpine.data('miniPaymentLanding', (config = {}) => ({
                 this.loading = false;
                 return;
             }
-            this.checkoutUrl = data.checkout_url;
-            this.showSheet = true;
-            this.loading = false;
+            this.checkoutUrl = data.checkout_url || data.authorization_url || '';
+            this.accessCode = data.access_code || '';
+            this.returnUrl = data.callback_url || this.returnUrl || '';
+            this.showSheet = true; // loading cleared when payment UI opens (ladill-pay-opened)
         } catch (e) {
             window.LadillPayCheckout?.cancel?.(); this.errorMsg = 'Network error. Please try again.';
             this.loading = false;