Distinguish a missing route from auth/config with a 405-vs-404 probe

When a CLI subcommand (e.g. status/whoami) returns HTTP 404 but the tools other commands still work, the client is probably calling an endpoint the deployed backend does not have. Curl the failing route and a known-good sibling: a POST-only route answers GET with 405 (route exists), a genuinely absent route answers 404. A FastAPI body of {"detail":"Not Found"} confirms the route is unregistered server-side, not an auth or config issue. Fix server-side or pin the client back to before that call was added.