Agent Skills: review

Self-review of code changes (branch diff, staged, or uncommitted). Use when: reviewing code before pushing, checking diff quality, self-reviewing a PR, creating a PR (always use --peer), reviewing uncommitted work. Triggers on: '/review', 'review my changes', 'review this branch', 'self-review', 'pre-push review', 'review uncommitted', 'review staged', 'create PR', 'open PR', 'submit PR'.