Add adversarial review and remove orchestrate work

[ferueda]

Summary

• add a packaged adversarial review skill for stress-testing proposed directions before implementation planning
• define independent reviewer lenses, evidence-backed finding criteria, and synthesis rules
• remove the packaged orchestrate-work skill and its obsolete contract test

Verification

• skill-creator quick validator
• pnpm exec vitest run test/skills.test.ts
• make check