Oh, WOW! I was looking for something just like this recently.

I tried setting up Theia (https://theia-ide.org) on windows and it was definitely not ready for major use.

I didn't find anything else that fit the bill either, I hear something like this exists internally at google though.

I'm not typically a huge fan of Github (I'm sure that's a controversial opinion) but this is definitely something I'm going to check out.