I am quite keen on this as well, I have been trying to move all my active development to happen inside a container, including the harnesses. This, of course, makes it very hard to run GUI harnesses. I prefer CLI, but it would be neat to be able to better isolate gui-based harnesses as well.

I have been using VSCodium with https://github.com/jeanp413/open-remote-ssh so (most of) the IDE also runs inside the container. I have been trying to get everything inside the container, including the projects I work on, the IDE, the harness, the dependencies, etc. Both for security and for portability so I can have the same setup in both my work and home computers.

One thing I haven't been able to do is limit the blast radius of is git, github ssh keys give blanket access to all repos tied to my profile and ATM I set up the github SSH key inside the container.