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.

prisma/migrations/20260105162935_add_stock_view/migration.sql

@@ -0,0 +1,17 @@
+CREATE OR REPLACE VIEW Stock_Available_View AS
+SELECT
+    sb.productId,
+    sb.inventoryId,
+    sb.quantity AS physicalQuantity,
+    COALESCE(SUM(sr.quantity), 0) AS reservedQuantity,
+    (
+        sb.quantity - COALESCE(SUM(sr.quantity), 0)
+    ) AS availableQuantity
+FROM
+    Stock_Balance sb
+    LEFT JOIN Stock_Reservations sr ON sr.productId = sb.productId
+    AND sr.inventoryId = sb.inventoryId
+GROUP BY
+    sb.productId,
+    sb.inventoryId,
+    sb.quantity;