I wrote a time-tracking Windows desktop program called Timesheet Sidekick. I think the free trial version meets your requirements. The trial version has some limitations, but you can use it as long as you like, and it might meet your needs as-is. (Though I expect that in the 3 years since you asked this, you have since found another solution!)
There is a ...
Sigrok/Pulseview (download) is probably the tool of choice here.
open-source preferred: Gnu GPL v3
windows-10: yes, it seems to go down to Windows XP
decodes 1-wire protocol: yes, and 116 other protocols
supports at least 4 channels: yes
ideally supports 8 channels: yes, and even up to 34 if you have the right hardware
can record ...
I think Etar deserves a mention.
Edit: I noticed deleted events (even from years ago) in my .ics export, like you mentioned. I investigated, and initially thought that the problem didn't happen with Etar, so I mistakenly thought Samsung's S Planner was the culprit. However, I tried to reproduce the problem again, and found out that whether this problem ...