Update Mass variants

Mass Update Variant Cost module enables bulk update of cost price across multiple product variants in one action. An “Update Cost” option appears in the action menu of the variant list view to launch a cost-update wizard. The wizard lets setting of a new cost price which then applies to all selected variants simultaneously. All changes reflect immediately in variant records. The feature is lightweight and cleanly integrated into product and inventory workflows. Cost update logic requires minimal lines of code, which ensures high performance.