feat: add discount functionality to sales and purchase transactions

- Introduced discount_type and discount fields in Bills and SalesReceipts controllers.
- Updated database migrations to include discount and discount_type in estimates and credit notes tables.
- Enhanced SaleReceipt and SaleEstimate models to support discount attributes.
- Implemented formatting for discount amounts in transformers and PDF templates.
- Updated email templates to display discount information.

This commit enhances the handling of discounts across various transaction types, improving the overall functionality and user experience.

packages/server/src/models/CreditNote.ts

@@ -43,8 +43,18 @@ export default class CreditNote extends mixin(TenantModel, [
       'isPublished',
       'isOpen',
       'isClosed',
+
       'creditsRemaining',
       'creditsUsed',
+
+      'subtotal',
+      'subtotalLocal',
+
+      'discountAmount',
+      'discountPercentage',
+
+      'total',
+      'totalLocal',
     ];
   }
 

packages/server/src/models/PaymentReceive.ts

@@ -11,6 +11,10 @@ export default class PaymentReceive extends mixin(TenantModel, [
   CustomViewBaseModel,
   ModelSearchable,
 ]) {
+  amount!: number;
+  paymentAmount!: number;
+  exchangeRate!: number;
+
   /**
    * Table name.
    */
@@ -40,6 +44,10 @@ export default class PaymentReceive extends mixin(TenantModel, [
     return this.amount * this.exchangeRate;
   }
 
+  /**
+   * Payment receive total.
+   * @returns {number}
+   */
   get total() {
     return this.paymentAmount;
   }

packages/server/src/models/SaleEstimate.ts

@@ -43,6 +43,8 @@ export default class SaleEstimate extends mixin(TenantModel, [
   static get virtualAttributes() {
     return [
       'localAmount',
+      'discountAmount',
+      'discountPercentage',
       'isDelivered',
       'isExpired',
       'isConvertedToInvoice',

packages/server/src/models/SaleInvoice.ts

@@ -72,6 +72,7 @@ export default class SaleInvoice extends mixin(TenantModel, [
 
       'taxAmountWithheldLocal',
       'discountAmount',
+      'discountPercentage',
 
       'total',
       'totalLocal',

packages/server/src/models/SaleReceipt.ts

@@ -40,7 +40,21 @@ export default class SaleReceipt extends mixin(TenantModel, [
    * Virtual attributes.
    */
   static get virtualAttributes() {
-    return ['localAmount', 'isClosed', 'isDraft'];
+    return [
+      'localAmount',
+
+      'subtotal',
+      'subtotalLocal',
+
+      'total',
+      'totalLocal',
+
+      'discountAmount',
+      'discountPercentage',
+
+      'isClosed',
+      'isDraft',
+    ];
   }
 
   /**