Refresh the package manager comparison with Bun

[ulises-jeremias]

Summary

Update the package manager comparison to include modern Bun behavior alongside npm, pnpm, and yarn.

Context

The repository includes package manager reference material. Bun has matured since the original issue was opened, so the comparison should be refreshed with reproducible measurements and a practical recommendation.

Scope

• Review the existing examples/node-package-managers content.
• Add Bun to the comparison.
• Document test environment, commands, and caveats.

Acceptance Criteria

• Compare install speed, disk usage, lockfile behavior, workspace support, and CI compatibility.
• Include reproducible commands.
• Include a recommendation section with tradeoffs.
• Keep the guide neutral and evidence-based.

Validation

• Run the documented benchmark commands locally where feasible.
• Run markdown lint checks if documented.

Contribution Notes

This is a good first issue for contributors interested in tooling research and documentation.