Add contract review skill

[KidSkills]

Summary

• Add the contract-review skill package.
• The skill reviews contract clauses against a supplied playbook.
• It emits extracted clauses, playbook-cited redlines, and a read-only risk summary without performing legal or contract effects.
• Register the new public official skill in both generated lock tables:
  packages/cli/src/official-skills.lock.json and
  crates/runx-cli/src/official_skills.rs.

Verification

• node skills\contract-review\test.mjs
• runx-cli 0.6.13
• runx skill inspect skills\contract-review -j
• git diff --check HEAD~1..HEAD
• Tracked official catalog parity check for public skill lock membership

Harness Cases

• playbook-redlines: contract yields extracted clauses and playbook-cited redlines.
• non-contract-refused: non-contract input is refused without clauses or redlines.