Streamlined level building experience (e.g. `build level -noPrompts`)

Would be nice if build level had some sub commands that don't pop up the initial into explanation and/or confirmations when hint and description aren't set, e.g. build level -noPrompts.

I'm currently building several levels and need to dismiss these pop-ups every time (first world problem to be sure...). Also, IMHO the experience should start with a trivial tree (single c0 initial commit with HEAD=main pointing to it).