you got it right, /tmp was full. I deleted dozens of tmp*.fit files created by indi-allsky and it should have enough space again. The exposure error went away with the sunset happening right now. Yes, I have used/tested libcamera with JPEG mode. It provided excellent pictures. Would be nice if the same quality could be achieved with raw. The secret sauce of the PiHQ camera firmware should not be a well hidden enigma.
After the git pull and restart the System menu is working now, but the May 10 20:58:32 localhost [ERROR] ImageWorker001 image.processImage() #655: PermissionError: [Errno 13] Permission denied: '/var/lib/containers/storage/overlay' is still there.
With default exposure 0.01 it works now again.