Fahrenheit support, app status on the Users page, and cancellation alerts (SnowManager)

This release adds temperature unit choices, richer device insight on the Users page, and better notifications when contractors call off work.

Temperature in Fahrenheit or Celsius: Each company can now choose its temperature unit under Settings → Business. The choice applies everywhere temperatures appear, including the Forecast page, the weather box on dispatches, and weather tracker thresholds. Companies billing in US dollars default to Fahrenheit; everyone else defaults to Celsius until they choose.
App status on the Users page: A new App column shows each person's app version, an update badge when a newer version is available, and a location indicator (green when background location is working, red when it isn't) with a tooltip explaining what to change on the phone. The user details panel now includes an App section with device, OS, permissions, and when the phone last reported.

Alerts when a contractor cancels a route: When a contractor cancels an accepted route or address from the app, the company that sent the dispatch is now notified and its admins receive a push (including the reason, when one was given), so cancellations no longer go unnoticed.

Addresses with long key codes can be saved again: Addresses with key codes longer than 100 characters could not be saved and gave no feedback. The address form now accepts key codes up to 200 characters and inactive notes up to 1000 characters, so these addresses save normally.