feat(cron): monthly semantic doc-health audit caller (lane 3c)

[ArchonVII]

Context

Lane 3c of the document-policy rollout — epic ArchonVII/archon-setup#223, spec ArchonVII/archon-setup#224 (§5.3). The semantic half of doc-health: what deterministic checks can't catch.

Scope

• Monthly cron caller per the doc-sweep cron precedent (PR feat(workflow): doc-orphan-detector cron backstop (doc-sweep §4.7) #45), targeting lifecycle: active registry repos.
• Agent audit pass per repo: contradictions between docs, irrelevant/carried-away content, vision drift (recent merged PRs vs VISION.md Scope).
• Output: report + filed issues per finding. Never edits docs. On-demand invocation also supported (OD3).

Acceptance Criteria

• Scoped actionlint on changed workflow files.
• Permissions block audited; tag-ref alignment checked; integration test present (reusable-workflow review rule).
• Dry-run produces a report and zero writes to target repos.

Deps: ArchonVII/repo-template#74 (checker + contract define the deterministic baseline this complements).