Comment by DustinBrett

It does indeed have a long way to go if I want to add usefulness beyond my personal website use case.

It is possible to "map" a local drive in several ways, such as via the desktop right click menu's "Map directory", and also if you built it locally you could put a folder in "public" which would then be mapped.

But it isn't the same as what you are describing and that would likely require a server component so I could bypass the limits of the browser.

I hope to eventually have an answer for all the use cases you mention, but because this is just a side project and my main goal is a client-side personal website, I don't expect those features in the 2020's, maybe the 2030's. :-)