chore: 🤖 convert DS build to tsup, add explicit vanilla export

[ArrayKnight]

Swapped Rollup out for TSup

Notes:

• I wasn't able to get the nested structure to work, so right now it's just bundling
• Due to renaming limitations in ESBuild, styles.css is now index.css, but the import in the app should be the same(?) since I updated the exports on the package.json
• Due to renaming and configuration limitations (and not wanting to write another custom plugin), the vanilla export is created from a new vanilla entry point. This allows for complete control over what is exported, but is a more manual process. Maybe there's a future way for this file to be generated based on a glob
• You'll see chunks in the dist. But they appear to be valid sharing of code / types between the exports without mixing anything into vanilla that we don't want

[brandonjpierce]

I don't know the ramifications of this, but currently the dist/index.js file and dist/vanilla.js file are exporting the same things (with dist/index.js additional ones from same chunk file):

dist/vanilla.js

dist/index.js

[brandonjpierce]

I tried doing an experiment with running three separate tsup configs one for each of our intended outputs, but was unable to get it working (or more accurately, matching the current output of the dist to a degree). If we wanted to hyper optimize the bundle output we may need to slightly restructure the package structure a smidge.