Diagnose which org this identity resolves to and whether its devices are visible

Read-only self-diagnosis for the CLI-login path. For the CALLER only: which org does the identity link point at, does that org still exist, and how many active devices does it hold. link_dangling: true — or a device count that disagrees with what the CLI just registered — is the signature of the identity-link drift that makes the portal report 'No devices registered yet' while <product> login reports success.