The non-interactive `login_with_credentials` path already speaks to
`AuthServiceClient` via gRPC. The interactive login / MFA / refresh
paths still return simulated responses — reword the inline comments
and the `tracing::debug!` messages to describe that split plainly
rather than labelling the gRPC-less paths as TODOs. The SECURITY
warn!() lines are untouched so the runtime signal remains.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>