Partner and vendor ownership

A PARTNER owns the shared catalog relationship; a VENDOR is associated through partnerId. The web application uses that relationship to inherit catalog settings and to determine category scope.

When the partner has CATALOG_MODE: true, the vendor's effective organization context also reports catalog mode on. A partner may select its own organization or one of its vendors for category operations; a vendor cannot use a supplied organizationId to escape its own scope. Without a target organization, a partner category listing aggregates its vendors, while category creation defaults to the partner itself.

This is why the edit form passes the product owner's organization to category autocomplete: a partner editing a vendor-owned product needs that vendor's categories, not an implicit partner-wide lookup. Exact endpoint behavior is in Categories API.