Define the dev-facing CLI contract: `harmony <scope> <verb>` grammar,
mandatory explicit context (no default), declarative/operational verb
split, three config homes, per-env profile tag, and the machine/agent
contract. Add the living CLI use-case & command guide and register it in
the mdbook nav. Mark ADR-012 superseded by 025.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Sylvain Tremblay
51c9499c55