Issue with cd per window

Thanks for this script, it's awesome!

I found an issue with getting the cwds restored per window. Fixed it and adjusted the script a bit to my liking. I can create a PR if you find some of these changes useful:

https://github.com/RanzQ/kitty-save-session/commit/80d8377039f0dadd6707ba4de9d9e69cd4719397