feat: add documentation staleness checks to issue-lifecycle skill

[stack72]

Summary

• Adds a documentation impact check as a new planning step (step 6) in the issue-lifecycle skill, requiring plans to evaluate whether changes affect design/*.md or .claude/skills/ and include update steps if so
• Adds "Documentation" as a new adversarial review dimension alongside architecture, scope, risk, testing, complexity, and correctness
• Adds stale doc/skill verification to the codebase verification checklist, so the adversarial reviewer actively checks referenced design docs and skills against planned changes
• Adds documentation as a valid finding category for adversarial review findings

Why

Design docs and skills drift out of sync with the codebase when PRs change behavior without updating the documentation that describes it. This is hard to catch after the fact because the people making changes have the context at planning time but not later. By embedding the check into the issue-lifecycle adversarial review — which already blocks approval on unresolved findings — we catch documentation gaps before code is written, when the fix is cheap.

Impact

Every issue triaged through the issue-lifecycle model will now have documentation impact evaluated at two points:

1. Planning — the plan must include doc/skill update steps if the change warrants them
2. Adversarial review — gaps are flagged as findings that block approval if severity is high/critical

This is a skill-only change with no code changes. It modifies the instructions that guide Claude's behavior during issue triage and plan review.

Test plan

• Triage a test issue that changes CLI behavior and verify the plan includes a skill update step
• Triage a test issue that changes domain concepts and verify the adversarial review flags missing design doc updates
• Triage a trivial bug fix and verify no false-positive documentation findings are raised

🤖 Generated with Claude Code