Add a code review skill for AI

[cclauss]

Added guidelines for code review process in SKILL.md.

@priya-sundaram-dev

Describe your change:

• Add a skill?
• Fix a bug or typo in an existing algorithm?
• Add or change doctests? -- Note: Please avoid changing both code and tests in a single pull request.
• Documentation change?

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• All new Python files are placed inside an existing directory.
• All filenames are in all lowercase characters with no spaces or dashes.
• All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• All functions have doctests that pass the automated testing.
• All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
• If this pull request resolves one or more open issues, then the description above includes the issue number(s) with a closing keyword: "Fixes #ISSUE-NUMBER".

[priya-sundaram-dev]

Nice — a dedicated code-review skill is the right call (keeps AGENTS.md focused). A few suggestions to make it something a reviewer can execute the same way every time:

1. Mirror the CONTRIBUTING.md section anchors explicitly, so nothing is skipped. CONTRIBUTING.md has: Before contributing, What is an Algorithm?, Coding Style, and Other Requirements for Submissions. Naming each as a checklist item makes the review reproducible.

2. Give the review a fixed output shape. Something like:

### Is this an algorithm? — <yes/no + why>
### Duplicate / prior-art check — <found #NNNN | none>
### Coding style — <pass | issues: …>
### Other requirements (doctests, type hints, descriptive names, Wikipedia URL) — <pass | issues: …>
### Verdict — <approve | request changes | close> + one-line reason

Consistent shape makes it easy to compare reviews and to automate label suggestions later.

3. Turn the prose questions into checkable items, e.g.:

• Adds exactly one algorithm (not multiple; not both code + test changes in one PR)
• Not already present in the repo (searched existing dirs)
• No earlier open PR does the same thing (link it if so)
• All new files: lowercase, no spaces/dashes; placed in an existing directory
• Public functions have type hints and doctests that pass
• At least one Wikipedia (or equivalent) URL for the algorithm
• Proper attribution — no plagiarism

4. Add a short tone rule: reviews should be specific and kind — cite the exact CONTRIBUTING.md rule and suggest the fix, not just "rejected". That keeps first-time Hacktoberfest contributors coming back.

5. Map findings to the existing labels (awaiting reviews, require tests, require type hints, require descriptive names, tests are failing) so a review naturally produces the label the cleanup scripts key off.

Happy to open a follow-up PR expanding SKILL.md along these lines if you'd rather see it as a concrete diff than a comment — your call. Either way this is a solid foundation.

[cclauss]

Yes, Priya, please create your separate pr for the .github/skills/code-review/SKILL.md file.

[priya-sundaram-dev]

Done — opened #15171 with the expanded SKILL.md (credited you for the original draft). Judge it as a concrete diff; happy to adjust.