Validates one serialized supply chain object (SCO) for either a website or an app and verifies the sellers it declares against the published authorized-seller records (ads.txt / app-ads.txt) and the sellers.json entry of each declared seller. Send the serialized SCO string as sco and, as id, either the publisher domain or the app's bundle ID — use this endpoint when a single integration submits both supply types. The response reports a status of valid, invalid, or error, together with the reasons codes behind that verdict — covering both problems with the SCO itself (101, 102) and problems with the authorization of the entities it declares (201-209).