Add formulas/AGENTS.md documenting sense vs act type distinction,
cron conventions, step ID naming rules, TOML structure skeleton,
and a how-to-add-a-new-formula walkthrough.
Add scripts/harb-evaluator/AGENTS.md covering the evaluator runtime:
directory layout, exit code convention, stack lifecycle, evidence
output, and how to add a new evaluator script.
Update root AGENTS.md directory map to link both new files.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
