idea-audit: attacker never re-checks claims tagged observed directly #390

idea-audit's attacker skips every claim the analyst tagged 'observed directly' (skills/workflow/idea-audit/references/attacker-brief.md:43), so the maker's label decides what the checker never re-checks. Fix: require the attacker to re-check a sample of those claims. Test: doc check on the brief text.

From the 2026-10-03 pstack-claude adoption audit (docs/research/pstack-claude-audit-2026-10-03.md, PR #385). Constraints: bash 3.2 and Python 3.9, failing test first (Rule 4), no hardcoded home paths, stage by name.