feat(inventory): add origin field to InventoryItem and update related DTOs and services

backend/prisma/migrations/20260419100000_add_inventory_origin/migration.sql

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

backend/prisma/schema.prisma

@@ -89,6 +89,7 @@ model InventoryItem {
   quantity       Decimal  @db.Decimal(10, 2)
   unit           String
   brand		 String?
+  origin         String?
   receiptName    String?
   location       String?
   purchaseDate   DateTime?