[enhancement] handle exit when stopwatch/timer is running
If stopwatch/timer is running and user quit,
app should take care of this situation:
- warns user about stopwatch/timer is running
1a. ask user stop it/them
1b. propose to continue running it/them and show a notification - quit but stop stopwatch/timer
this would fix the issue of accidental quitting and improve app usage because it is not normal (especially in the smartphone era) behaviour of stopping a running thing without user interaction