feat: add receiptName field to InventoryItem model and update related DTOs and service

backend/prisma/migrations/20260416210000_add_receipt_name_to_inventory/migration.sql

@@ -0,0 +1,2 @@
+-- AlterTable
+ALTER TABLE `InventoryItem` ADD COLUMN `receiptName` VARCHAR(191) NULL;

backend/prisma/schema.prisma

@@ -30,6 +30,7 @@ model InventoryItem {
   quantity       Decimal  @db.Decimal(10, 2)
   unit           String
   brand		 String?
+  receiptName    String?
   location       String?
   priority       Int?
   purchaseDate   DateTime?