feat(skills): add code-reviewer skill

[sehoon38]

Summary

This PR introduces a new code-reviewer skill to the Gemini CLI. This skill empowers the agent to conduct comprehensive code reviews for both local changes and remote Pull Requests, focusing on correctness, maintainability, readability, efficiency, security, and testability.
This is based of pr-review.toml we have that is used for command /oncall:pr-review.

Details

The code-reviewer skill provides a structured workflow for:

• Identifying the review target: Distinguishing between remote PRs (by ID/URL) and local changes.
• Preparation: Handling checkout (for remote PRs), running preflight checks, and gathering context.
• In-Depth Analysis: Guiding the agent to evaluate code based on key engineering pillars.
• Feedback: Structuring feedback with a summary, prioritized findings (Critical, Improvements, Nitpicks), and a clear conclusion.
• Cleanup: Offering to switch back to the main branch after reviewing remote PRs.

This addition aims to standardize and elevate the quality of code reviews
performed by the agent.

Related Issues

N/A

How to Validate

1. Install/Update: Ensure the skill file is present in .gemini/skills/code-reviewer/SKILL.md.
2. Activate: Run activate_skill('code-reviewer').
3. Test Local Review: Make some local changes and ask the agent to "review my code". Verify it follows the skill's workflow.
4. Test Remote Review: Ask the agent to "review PR #xyz" (using a valid PR number). or review local change.

Pre-Merge Checklist

• Updated relevant documentation and README (if needed)
• Added/updated tests (if needed)
• Noted breaking changes (if any)
• Validated on required platforms/methods:
  • MacOS
    • npm run
    • npx
    • Docker
    • Podman
    • Seatbelt
  • Windows
    • npm run
    • npx
    • Docker
  • Linux
    • npm run
    • npx
    • Docker

[gemini-code-assist]

Note

Gemini is unable to generate a summary for this pull request due to the file types involved not being currently supported.

[github-actions]

Size Change: -2 B (0%)

Total Size: 23.2 MB

ℹ️ View Unchanged

Filename	Size	Change
./bundle/gemini.js	23.2 MB	-2 B (0%)
./bundle/sandbox-macos-permissive-closed.sb	1.03 kB	0 B
./bundle/sandbox-macos-permissive-open.sb	890 B	0 B
./bundle/sandbox-macos-permissive-proxied.sb	1.31 kB	0 B
./bundle/sandbox-macos-restrictive-closed.sb	3.29 kB	0 B
./bundle/sandbox-macos-restrictive-open.sb	3.36 kB	0 B
./bundle/sandbox-macos-restrictive-proxied.sb	3.56 kB	0 B

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