Added repetition stepper to settings and changed time stepper to accommodate repetitions in settings

[notrandomath]

Summary of Changes:

• Added a new repetitions stepper to settings so that users can choose whether to end after a certain number of minutes or after a certain number of repetitions
• Changed time stepper to be in MM:SS format (or 1h to fit 01:00:00 without ellipsis)
  • Also made all steppers uniformly w-14
• Updates time stepper based on repetitions and vice versa

Here are demonstrations of what the new changes look like:
IOS, Android

Issues Fixed:
#125, #122

Potential Bugs:

• Towards the end of IOS demonstration there is a bug where the app doesn't handle times ending in 0.5 correctly and will briefly show 59:59:5 before ending
• I tested on iPhone 16 Pro simulator and the Medium Phone Android API (1080x2400 display), so I haven't confirmed correctness on smaller phone sizes

[0then0]

Hi @mmazzarolo! I noticed this PR has been open for a while. I'd be interested in working on #125 and bringing the implementation up to date with the current master.

Would it be helpful if I opened a new PR based on the current codebase?