5.70i [P1] — /openapi/v1 unknown route 404 carries canonical ErrorBody
(code, status) and must NOT contain flask-restx route suggestions
('did you mean'); pins the ExternalApi._help_on_404 fix from
PR #37285
5.70j [P1] — device-flow token endpoint returns RFC 8628 {error: string}
on failure, not the canonical ErrorBody shape; pins the
explicit RFC 8628 exception documented in PR #37285 and
confirms zErrorBody.safeParse would fail gracefully on this
shape (serverError = undefined, generic message, no crash)