Thanks, this was a real bug and it's fixed in the build I just uploaded. The upgrade panel was built once when you opened it and never refreshed, so buttons stayed greyed out even after you could afford them. It updates live now. Turned out the manifest had the same problem, so finds made while that panel was open never showed up either.
Balance also got a rework in this version. I ran the economy through a simulator and generators and smelters were hitting a hard cap where extra ones did literally nothing, so surplus scrap had nowhere useful to go. They now give diminishing returns instead of falling off a cliff.
Glad it's fun. Let me know if you hit anything else.