This repository treats documentation as a production interface. Tier 0–Tier 1 docs MUST be kept current; CI enforces a freshness SLA using docs/governance/freshness-policy.yml and frontmatter metadata.
Tier 0–Tier 1 documents MUST include YAML frontmatter:
owner: <team-or-handle>
last_reviewed: YYYY-MM-DD
tier: 0|1|2|3
last_reviewed exceeds the SLA threshold for the declared tier.