Preview an invitation (public — used from the email link)

{
  "success": true,
  "data": {
    "email": "invitee@example.com",
    "scope_name": "Acme Corp",
    "role": "admin",
    "expires_at": "2026-02-12T00:00:00.000Z",
    "status": "pending"
  }
}