ci: add Claude PR review agent

[thomaspinder]

Summary

A PR comment that mentions @claude-pr-review runs a Claude reviewer agent on that PR. The agent follows the existing PR Review Policy in AGENTS.md and the procedure and output format in .claude/commands/pr-review.md. Text after the mention reaches the agent as extra instructions, for example @claude-pr-review focus on the identification code.

 .claude/
+├── agents/pr-reviewer.md      # points at the policy + /pr-review, with CI changes
 └── commands/pr-review.md      # unchanged, still the source of the review format
 .github/workflows/
+└── claude-pr-review.yml       # issue_comment -> anthropics/claude-code-action

on PR comment
  if the comment mentions @claude-pr-review and the author is thomaspinder
    claude-code-action --agent pr-reviewer
      gh pr view, gh pr diff            # instead of git diff origin/$BASE_REF...HEAD
      inline comment on each in-scope finding
      full In-Scope / Out-of-Scope review in the tracking comment   # instead of gh pr comment

Notes:

• The action restores .claude/ from the PR's base branch before Claude starts. A PR cannot change the instructions of its own reviewer, and changes to the agent or to /pr-review take effect after merge.
• The run uses a Claude subscription through the CLAUDE_CODE_OAUTH_TOKEN secret. The first run needs the Claude GitHub App on this repo and that secret.

Evidence

• prek run --files .claude/agents/pr-reviewer.md .github/workflows/claude-pr-review.yml: all hooks pass (check yaml, end-of-file, trailing whitespace).
• Local agent load check:

  claude -p --agent pr-reviewer "quote the sentence that begins 'You review pull requests for'"
    -> "You review pull requests for Impulso."
  

• Not yet run end to end on GitHub: that needs the App and the secret.

Merge Danger

Door: two-way

Delete the two files to revert.

Blast Radius: isolated

The workflow runs only on PR comments that mention @claude-pr-review and come from thomaspinder. No library code, test, docs or release workflow changes. Each run uses Claude subscription quota.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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