Pending browser-based OAuth login state returned by Codex.OAuth.begin_login/1.
Codex.OAuth.begin_login/1
@type t() :: %Codex.OAuth.Session.PendingLogin{ authorize_url: String.t(), context: struct(), flow: atom(), loopback_server: struct() | nil, pkce: struct(), provider: atom(), redirect_uri: String.t(), state: String.t(), storage: :file | :memory | :auto, warnings: [String.t()] | nil }