Update listing import policy

Change this setting before requesting import or reconciliation. The body has one decision, policy, but it has important effects on automatic Product, Variant, and binding creation for all future external offers of that Connection.

Choose unlinked for inspection first; match_only when your local SKUs/GTINs are reliable; and match_or_create when you accept minimum quarantine records for every variation that has no unique match. A title never enters the algorithm.

The change is local and returns the updated Connection. It does not start a Job, read the marketplace, change an existing Listing policy, or repair bindings already created. After changing it, deliberately import listings or reconcile.