ci: remove claude-code-review workflow (#6565)

## Summary
- Remove the `claude-code-review.yml` CI workflow that was neutered for
security reasons but continued to fail on every PR
- The `claude.yml` workflow (for `@claude` mentions) is unaffected

## Test plan
- [x] Verify existing PRs no longer show the failing check

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: westonpace