CLI to create `filename.twoslash.json` along with `filename.md` for pre-rendered content

We could have a standalone cli (also related to #14) that pass run Twoslash ahead of time to generate `xxx.twoslash.json` along with each markdown file, to serve as caches for other integrations to consume directly without the computational cost and complex setup, idea brought up by @danielroe at https://github.com/nuxt/nuxt/pull/31353#issuecomment-2727339251