Lists items below one of their reorder points, with on-hand, reorder quantity and vendor.

Requires ViewInventory. One line per active reorder point whose watched stock is strictly below its minimumStock — an item with reorder points at two locations can appear twice. Stock is the count of non-deleted units at the reorder point's location, or everywhere when it has none (the Reorder page's rule). vendorId is the item's preferred vendor (set on Item Templates → Edit or PATCH /api/v1/items/{id}), else the vendor of the CSV import that created it. Computed on request and read-only: unlike opening the Reorder page it raises no alert and fires no inventory.low_stock webhook. Ordered by item name then location. Not cursor-paginated (the list is bounded by the reorder points): everything comes back with nextCursor always null. Example: GET /api/v1/items/low-stock?vendorId=3. Also available as CSV (Accept: text/csv or ?format=csv); paging cursor in X-Next-Cursor.