chore: add REVIEW.md, update AI review docs

[paulbalaji]

Summary

• Adds a REVIEW.md file to guide Claude Code's automated PR review feature
• Defines what reviewers should always flag (security issues, type safety violations, missing tests)
• Defines what to skip (formatting, style handled by linters)
• Complements existing CLAUDE.md review guidelines with review-specific rules

Context

Claude Code now supports REVIEW.md files for review-specific guidance, separate from CLAUDE.md.

🤖 Generated with Claude Code

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Note

Low Risk
Documentation/guideline-only changes with no runtime behavior impact; risk is limited to reviewers following the new guidance.

Overview
Adds a new top-level REVIEW.md containing consolidated, repo-specific code review guidelines (including a mandatory type-cast/any audit and testing/changeset expectations).

Updates the claude-review skill documentation to reference REVIEW.md instead of the previous .github/prompts/code-review.md guidance.

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[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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[claude]

LGTM, straightforward documentation change with no runtime impact.

Extended reasoning...

Overview

This PR modifies two documentation files: REVIEW.md (updated header from a prompt-style instruction to a proper markdown title, removed 3 trailing instruction lines) and .claude/skills/claude-review/SKILL.md (updated file path reference from .github/prompts/code-review.md to REVIEW.md). No code, configuration, or runtime behavior is changed.

Security risks

None. These are purely documentation/guideline files that instruct AI review tools. No code execution paths are affected.

Level of scrutiny

Minimal scrutiny needed. This is a low-risk documentation reorganization. The content of the review guidelines themselves is unchanged — only the file location and formatting wrapper changed. The cursor[bot] duplication concern was already marked as resolved in the PR timeline.

Other factors

The recent commit history on master (9e046b5 Refactor claude-review skill to use REVIEW.md, remove code-review.md) confirms the old .github/prompts/code-review.md file has been removed, so the SKILL.md path update is necessary and correct. No outstanding reviewer comments remain unaddressed.