Updates scripts/agent/review-pr.mjs to fetch the base branch of PRs and
include specific release channel guidance (Main vs Unstable) in the
automated review report, as per AGENTS.md instructions.
- Adds `scripts/agent/review-pr.mjs` to automate PR checks (lint, format, test).
- Implements micro-fix logic to auto-commit formatting changes.
- Adds guardrails for sensitive files (security/protocol review).
- Generates a Markdown report with test failure analysis.