This PR adds support for .supplementalActivityFamilies([.small]), allowing the Live Activity to appear in the Apple Watch Smart Stack (starting with iOS 18) and in CarPlay (starting with iOS 26). Because iOS 17 does not support this family, the code is restructured a bit to provide a different view in that case. Note that I have not tested this on an actual iOS 17 device.

In addition, this PR addresses the following issues:

• Make the point size smaller on the graph to reduce crowding
• Update the color of the glucose points and prediction line on the graph to use the Loop standard .glucose color.
• Change the dash style of the prediction line to match the graph in the main Loop app

Known remaining issues:

• This does not address the issue flagged in the original PR about replacing "IOB" and "COB" with "Active insulin" and "Active carbs". That will require a more fundamental change to the layout of the main display, possibly to add another label row and/or to reduce the number of displayed items.
• It should be possible to tap on the Live Activity in the Watch Smart Stack and get it to launch the Watch app (described at 5:35 in (this video)[https://developer.apple.com/videos/play/wwdc2024/10068/]). I tried adding that flag, but I was unable to get that to work.
• There is a bug in iOS 26.0.1 that sometimes causes doubled images in the CarPlay display - the previous text is not cleared when new text is displayed, if the phone screen is off. This appears to be fixed in iOS 26.1 beta 4.

Let me know if you have questions!