enhancement: Ability to label the current time block with a short description of the task at hand

[evilbuck]

When working on a task, I as a user would like to be able to glance up at the pinned timer and see a title/label about the task I'm supposed to be on.

When starting a new timer, I as a user would like to be able to name the task easily using keyboard navigation. Possibly as a prompt that can be easily dismissed or a field that could be tabbed to when starting the timer.

I as a user would like the ability to turn on or off the labeling of a task feature in the settings. So that I would not need to see the feature if I did not want to use it.