Add procurement domain models (PurchaseOrder, GoodsReceipt, PurchaseReturn)

Distribution/Models/GoodsReceipt.cs

@@ -0,0 +1,26 @@
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace Distribution.Models
+{
+    public class GoodsReceipt : Template
+    {
+        public Guid FK_PurchaseOrderId { get; set; }
+        [ForeignKey("FK_PurchaseOrderId")]
+        public PurchaseOrder PurchaseOrder { get; set; }
+
+        public Guid FK_ReceivedByUserId { get; set; }
+
+        /// <summary>
+        /// Warehouse the accepted quantities are received into. Not listed as a field in
+        /// docs/15_procurement.md's GoodsReceipt table, but required to write StockBalance/
+        /// StockMovement rows (both keyed by LocationId+LocationType) for the accepted quantities.
+        /// </summary>
+        public Guid FK_WarehouseId { get; set; }
+        [ForeignKey("FK_WarehouseId")]
+        public Warehouse Warehouse { get; set; }
+
+        public DateTime ReceivedAt { get; set; } = DateTime.Now;
+
+        public ICollection<GoodsReceiptItem> Items { get; set; } = [];
+    }
+}