Critique a Git Diff

Analyze a git diff, identify issues, and produce a review.xml file that can be loaded into self-review via --resume-from for human validation. The first step generates the walkthrough guide sidecar via the self-review-guide skill, so a critique run yields both artifacts.

XML Reference

Non-obvious semantics (keep in sync with ../self-review-apply/assets/self-review-v3.xsd):