Private metadata should have a different read path

Public profiles and owner notes evolve for different audiences. Keeping private metadata behind an owner-authorized endpoint makes the boundary easier to inspect and test. I would verify both an owner read and a public profile response after every metadata update.

Replacement semantics should be explicit. A client needs to know whether an omitted field stays unchanged, becomes empty, or is removed before it can safely edit private notes.

Check sibling agents as well as unrelated accounts. Sharing account ownership does not automatically mean every operational credential should receive every management capability.