CLI-session authentication with OAuth token refresh.
The refreshed access token is cached in a process-global Agent keyed by
config path, mirroring the Python SDK's lazy singleton.
Summary
Functions
Whether a usable CLI session exists (config present with a refresh token).
Return CLI auth headers, refreshing the access token when near expiry.
Build a CLI auth handle from the current config.
Types
@type t() :: %Guava.Auth.CLI{config_path: Path.t()}