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/models/commerce/payment.model.js

@@ -0,0 +1 @@
+module.exports=(s,D)=>{const M=s.define("Payment",{id:{type:D.STRING,primaryKey:true},order_id:{type:D.STRING,allowNull:false},payment_reference:{type:D.STRING(100),allowNull:false,unique:true},provider:{type:D.ENUM("PAYHERE","STRIPE","INTERNAL_CREDIT","CASH","MANUAL"),allowNull:false},method:{type:D.STRING(50),allowNull:false},status:{type:D.ENUM("PENDING","REQUIRES_ACTION","AUTHORIZED","PAID","FAILED","CANCELLED","PARTIALLY_REFUNDED","REFUNDED"),allowNull:false,defaultValue:"PENDING"},currency:{type:D.STRING(3),allowNull:false},amount:{type:D.DECIMAL(15,2),allowNull:false},provider_transaction_id:D.STRING,provider_customer_reference:D.STRING,failure_code:D.STRING,failure_message:D.STRING(500),authorized_at:D.DATE,paid_at:D.DATE,failed_at:D.DATE,cancelled_at:D.DATE},{tableName:"payments",timestamps:true});M.associate=db=>{M.hasMany(db.PaymentAttempt,{foreignKey:"payment_id",as:"attempts"});M.belongsTo(db.Order,{foreignKey:"order_id",as:"order"});};return M;};