Enable automatic Stripe receipt emails after payment

- Added payment_intent_data.receipt_email to checkout session
- Stripe will now automatically send receipt emails to customers after successful payment

server/routes/checkout.js

@@ -112,6 +112,9 @@ router.post('/create-session', async (req, res) => {
         baseAmount: baseAmount.toString(),
         processingFee: processingFee.toString(),
       },
+      payment_intent_data: {
+        receipt_email: customerEmail, // Send Stripe receipt email after successful payment
+      },
     });
 
     // Store order in database