[SPIKE] Rollup / Vitest / Shelljs -> Bun

[michael-gee]

For good reason, there is a lot of hype and excitement around Bun. This tool could potentially be a full replacement for both Vitest for local development/test AND Rollup for production builds.

Bun currently only supports ESM (image below) for production output but once it also supports CJS I will begin this spike.

Bun's Roadmap