How long have you been building this?

Six months. Basically when Claude code started to hit that inflection point I chose a project that seemed potentially impossible but was also something I care deeply about. (I have a lot of history with open source and CAD and I even made an open source CAD forum on GitHub a few years ago to discuss options.)

I set up remote tmux access to my phone right at the beginning so I have been advancing it rather continuously during my waking hours. Especially the last few months which have been a very focused push on a new kernel architecture.