App: task tracker / timer

This is just a UI that has a play / pause button to track time, something like Toggl.

I'm pretty sure the ideal implementation is for it to cache some pending EconomicEvents in localStorage, set a hasBeginning when activated, and store the final event with a hasEnd at the current time on stopping the timer. It also lets you tag those time trackings against ResourceSpecifications or ResourceClassifications; otherwise should be pretty straightforward.