Updated project changes

src/modules/payments/services/checkoutService.js

@@ -25,7 +25,7 @@ const getStripe = () => {
  * Create a session for an invoice and redirect to Stripe's hosted page.
  * Throws (with a friendly message) if the backend isn't configured/reachable.
  */
-export async function startCheckout({ invoiceId, customerEmail } = {}) {
+export async function startCheckout({ invoiceId, customerEmail, fallback } = {}) {
     if (!stripeConfig.isConfigured) {
         const err = new Error(
             'Stripe is not configured yet. Add your publishable key to enable payments.'
@@ -37,7 +37,9 @@ export async function startCheckout({ invoiceId, customerEmail } = {}) {
     const res = await fetch(`${stripeConfig.apiBase}/create-checkout-session`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
-        body: JSON.stringify({ invoiceId, customerEmail }),
+        // `fallback` carries the invoice's amount/title for demo invoices the
+        // owner created in localStorage (the server's static map won't have them).
+        body: JSON.stringify({ invoiceId, customerEmail, fallback }),
     });
 
     const data = await res.json().catch(() => ({}));