fix: ThankYou page discount rows and improved hidden field detection

1. ThankYou page - Added discount row to order summary
   - All 3 template variations (receipt-inner, receipt-outer, default)
   - Shows discount with negative amount in green when > 0
   - Already had shipping/tax rows, now complete breakdown

2. Checkout - Enhanced isFieldHidden helper
   - Now checks both type='hidden' AND hidden=true flags
   - Any standard field can be hidden via PHP snippet
   - Existing city/state/postcode/country checks unchanged

customer-spa/src/pages/Checkout/index.tsx

@@ -222,10 +222,11 @@ export default function Checkout() {
     loadCheckoutFields();
   }, [cart.items, isVirtualOnly]);
 
-  // Helper to check if a standard field should be hidden (set to type: 'hidden' in PHP)
+  // Helper to check if a standard field should be hidden (set to type: 'hidden' or hidden: true in PHP)
   const isFieldHidden = (fieldKey: string): boolean => {
     const field = checkoutFields.find(f => f.key === fieldKey);
-    return field?.type === 'hidden';
+    // Check both type='hidden' and the hidden flag from API
+    return field?.type === 'hidden' || field?.hidden === true;
   };
 
   // Filter custom fields by fieldset

customer-spa/src/pages/ThankYou/index.tsx

@@ -147,6 +147,12 @@ export default function ThankYou() {
                         <span className="font-mono">{formatPrice(parseFloat(order.tax_total))}</span>
                       </div>
                     )}
+                    {parseFloat(order.discount_total || 0) > 0 && (
+                      <div className="flex justify-between text-sm text-green-600">
+                        <span>DISCOUNT:</span>
+                        <span className="font-mono">-{formatPrice(parseFloat(order.discount_total))}</span>
+                      </div>
+                    )}
                     <div className="flex justify-between text-lg font-bold border-t-2 border-gray-900 pt-2 mt-2">
                       <span>TOTAL:</span>
                       <span className="font-mono">{formatPrice(parseFloat(order.total || 0))}</span>
@@ -263,6 +269,12 @@ export default function ThankYou() {
                       <span className="font-mono">{formatPrice(parseFloat(order.tax_total))}</span>
                     </div>
                   )}
+                  {parseFloat(order.discount_total || 0) > 0 && (
+                    <div className="flex justify-between text-sm text-green-600">
+                      <span>DISCOUNT:</span>
+                      <span className="font-mono">-{formatPrice(parseFloat(order.discount_total))}</span>
+                    </div>
+                  )}
                   <div className="flex justify-between text-lg font-bold border-t-2 border-gray-900 pt-2 mt-2">
                     <span>TOTAL:</span>
                     <span className="font-mono">{formatPrice(parseFloat(order.total || 0))}</span>
@@ -415,6 +427,12 @@ export default function ThankYou() {
                     <span>{formatPrice(parseFloat(order.tax_total))}</span>
                   </div>
                 )}
+                {parseFloat(order.discount_total || 0) > 0 && (
+                  <div className="flex justify-between text-green-600">
+                    <span>Discount</span>
+                    <span>-{formatPrice(parseFloat(order.discount_total))}</span>
+                  </div>
+                )}
                 <div className="flex justify-between font-bold text-lg text-gray-900 pt-2 border-t">
                   <span>Total</span>
                   <span>{formatPrice(parseFloat(order.total || 0))}</span>