Get the business or person who owns a property

The related resource URL of a property's owner relationship (JSON:API 1.1, "Related Resource Links"; decision 2026-10-28, G17): the business or the person who owns the property, each in its own shape (data.type is organization or user, as getOrganization and getUser return them). It is the relationship's links.related on getProperty, built from the property's id alone, so it never changes. A property always has an owner, and one whose owner is gone cannot be read at all, so data is never null in practice; the document keeps the related-resource shape. Read rights are the property's (getProperty): a stranger gets a 404 on a private property. Not an assistant's tool: an assistant reads the owner with getBusiness or getUser and is refused here (403).