Get Member Onboarding Status

Whether this member still owes the Google setup dialog for the active org.

POST rather than GET because a first-time evaluation PERSISTS its verdict — the rules run once per (user, org) and never again, so a member's own Confirm/Skip can never be re-derived away. The client only calls this when no status is recorded in its already-loaded users.preferences, so it costs at most one request per (user, org).