feat: implement POS order management system

- Added CreateOrderDto and CreateOrderItemDto for order creation.
- Developed PosOrdersController to handle order-related endpoints.
- Created PosOrdersService for business logic related to orders.
- Implemented PosOrdersWorkflow for order processing workflows.
- Established Prisma integration for database operations in orders.
- Introduced SalesInvoicesModule and related DTOs for sales invoice management.
- Enhanced SalesInvoicesService and SalesInvoicesWorkflow for invoice processing.

src/modules/sales-invoices/dto/create-sales-invoice.dto.ts

@@ -0,0 +1,20 @@
+import { Type } from 'class-transformer'
+import { IsInt, IsNumber, IsOptional, IsString } from 'class-validator'
+
+export class CreateSalesInvoiceDto {
+  @IsString()
+  code: string
+
+  @Type(() => Number)
+  @IsNumber()
+  totalAmount: number
+
+  @IsOptional()
+  @IsString()
+  description?: string
+
+  @IsOptional()
+  @Type(() => Number)
+  @IsInt()
+  customerId?: number
+}