GLAS-WP-0002 is now fully done (4/4): formalize the CLI as the first
Channel extension (contract + refactor + tests + second-channel
documentation), not building a second channel yet -- same
generalize-from-a-real-second-example discipline as ADR-002/ADR-004.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>