feat: Implement return and refund functionality in commerce module

- Added return request handling in return.controller.js
- Implemented webhook handling for PayHere payments in webhook.controller.js
- Created models for coupon redemptions, invoices, orders, order items, payments, payment attempts, payment webhook events, refunds, return items, and return requests.
- Developed services for order management, payment processing, refunds, and returns.
- Introduced validation schemas for payment and return requests.
- Created migration scripts for new database tables related to orders, payments, refunds, and returns.
- Added unit tests for order state transitions and PayHere provider functionality.

app/routes/commerce.routes.js

@@ -0,0 +1 @@
+const r=require("express").Router(),orders=require("../controllers/commerce/order.controller"),returns=require("../controllers/commerce/return.controller"),webhook=require("../controllers/commerce/webhook.controller"),{authenticate}=require("../middleware/auth.middleware"),validate=require("../middleware/validate.middleware"),s=require("../validation/commerce.schemas");r.post("/payments/webhooks/payhere",webhook.payhere);r.use(authenticate);r.get("/orders",orders.list);r.post("/orders/from-checkout",validate(s.fromCheckout),orders.create);r.get("/orders/:id",orders.get);r.post("/orders/:id/cancel",orders.cancel);r.post("/orders/:id/payment",validate(s.payment),orders.startPayment);r.get("/orders/:id/payment",orders.payment);r.get("/orders/:id/invoice",orders.invoice);r.post("/orders/:orderId/returns",validate(s.returnRequest),returns.request);r.get("/returns",returns.list);r.get("/returns/:id",returns.get);module.exports=r;