feat(oauth-client): wire CLI interactive arm to run_pipeline with WaitForExternalClient
Updates ClientCmd::run to properly wire the interactive subcommand. When
ClientMode::Interactive(args) is matched, creates an InteractiveOptions with
drive_mode: InteractiveDriveMode::WaitForExternalClient, and passes it to
run_pipeline via OauthClientOptions. Removes the Phase 6-8 placeholder
println. Static mode also updated to pass interactive: None.
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>