inventoryBulkAdjustQuantityAtLocation mutation is being removed—migrate to inventoryAdjustQuantities

Shopify is removing the `inventoryBulkAdjustQuantityAtLocation` mutation from its GraphQL Admin API. Developers must migrate to `inventoryAdjustQuantities`, which offers a more consistent approach for adjusting inventory across multiple items and locations. The changelog provides a before/after code example showing the key differences: the new mutation uses an `input` object with fields like `reason`, `name`, `referenceDocumentUri`, and a `changes` array that includes `locationId` per item rather than as a top-level parameter. Migration must be completed before the 2026-07 API version.