chore: Update GitHub Actions to use macos-latest runners

Using macos-latest ensures the CI always runs on the most current
macOS runner without requiring manual updates. This provides:
- Automatic updates to latest macOS versions
- Better performance and up-to-date tooling
- Consistent behavior with other 'latest' runners

- Updates .github/workflows/push.yml to use macos-latest
- Aligns with the test fix for macOS GitHub Actions paths