using a [babel plugin](https://gist.github.com/pengx17/49e24ae8a5a609bdaff122ee8c679d1c) to transform all var(--affine-xxx) to cssVar
Some issues:
- tried ast-grep but it seems to be not easy to add imports conditionally
- current work does not work well with ts with types because babel will strip them out
fix TOV-280
experimental features ui
- enabled in the workspace settings for a cloud workspace; only show for workspace owner + early access
- a disclaimer prompt will be shown before going to the next feature setting page
- for now only show the ai poc switch, which controls the display of the ai tab in editor's sidepanel
