Links Zuper products to a supplier's products: each entry pairs a Zuper product (and option) with a supplier product variant and unit of measure, and creates a vendor catalog row holding the supplier SKU, unit and cost so the product can be ordered from that supplier. Rows for the saved branch in vendor_uid are created immediately; the same entries are then applied to every other saved branch of this provider in the background. A row is created only where the branch stocks the item according to the branch stocking data Zuper syncs from the supplier, and its cost is the supplier's price at that branch, so entries the branch does not stock are returned in skipped_entries (if the supplier's price request fails for this branch, they are retried in the background). Zuper may reuse a supplier price answer for up to 15 minutes, so a price can be that old. A Zuper product can be linked to only one supplier product per supplier and each Zuper option to one supplier option; if any entry fails a check the whole request is rejected and nothing is saved. Each linked or skipped row is also recorded in the Zuper product's activity. Save the branch first with Create Supplier Branch. Instead of an option UID, an entry can name the Zuper option in zuper_product_option_name: Zuper reuses the product option with that name or creates it, and reports the outcome in data.zuper_option_resolutions. Admin only: the API key must belong to an admin user; other roles receive 405 Access Denied.