Support idle-exempt categories

Hi folks.
It would be great if AW supports idle-exempt categories which means any activity spent in these categories will not trigger an idle state, ensuring they are tracked even during periods of inactivity.
The typical use case is reading books and watching videos.
Regards.

Tried to implement in my https://github.com/AlexanderMakarov/activitywatch-ets - see Git, Jira, Outlook importers and separate way to categorize/aggregate events into activities for more details. Now finished to work on it because switched job and don’t have so strict requirements for time-sheets.