I agree a calendar would be a super useful feature especially because in this game unlike LLTQ we aren't pre warned about a ton of upcoming events the week before.
I'd like a feature that auto adds events you are told about but on subsequent playthroughs you could use to put reminders about upcoming events so that you can mentally plan to have the right stats for or remember to speak to an elector before they switch sides etc.
Maybe that's too in depth for what is effectively a really good notebook...