Docs Sync

• Check README.md, docs/DECISIONS.md, relevant docs under docs/, and any ADRs.
• Update docs in the same change as code when public behavior, commands, assumptions, or validation evidence changes.
• Record durable decisions in docs/DECISIONS.md or a new ADR; do not bury decisions only in chat.
• Keep docs concise and operational: what changed, why, how to run it, and what remains out of scope.
• Avoid rewriting unrelated docs or changing historical decisions except to add a dated superseding note.