Payroll report Net column fix + behind-the-scenes reliability

A targeted fix to a payroll report bug plus several behind-the-scenes improvements to system reliability.

What's Fixed

• Payroll report Net column shows correct hours — the Net column was showing 30 minutes short for every shift that had a break, because break time was being deducted twice. The Hours column shows gross worked time, the Breaks column shows total break time, and the Net column now correctly shows Hours minus Breaks.

What's Improved

• Less notification noise for admins without iPhones — push notification jobs no longer fan out to admins who don't have the FabWise iOS app installed. Cuts background-job noise and speeds up shift events for everyone.