feat(playground): Better oxlint config editor

[connorshea]

I think this would also be useful for the formatter config as well, in the future.

It'd be great if I could have a proper text editor to edit the linter config file with, rather than the current system where I have to escape the JSON because it's embedded inside the playground JSON itself, and I can only edit the raw json blob.

This would allow me to demonstrate and reproduce oxlint bugs/behavior a lot more easily in the future.