Run app view and notebook editor view together

[aidanmontare-fed]

Would it be possible to run the app view alongside the notebook view? That way I can see how my app will look to users while I also work on it's code.

I think either a split screen within marimo's browser tab, or opening this as a second browser tab would both be fine, as long as they could sync together.

I suppose one solution for now is to run a separate a separate instance of marimo run --watch NOTEBOOK, which looks like it will work okay. The state isn't shared, but I can at least get a glance of what my app looks like as I'm working.

[mscolnick]

marimo run --watch NOTEBOOK is the current recommended way

[liquidcarbon]

@aidanmontare-fed the --watch works but let's build appetite and demand for a little more ;) - see #2910