ChartsOrg/Charts ? reverse-engineered prompt

Build me a beautiful charting library for Apple platforms that feels polished and easy to drop into an app. I want it to work on iPhone, iPad, tvOS, and macOS, and I want a couple of demo apps so I can see how the charts look and how to use them.

The library should support the usual chart types people expect, like line, bar, pie, scatter, radar, and combined charts, with good looking defaults, smooth animations, labels, legends, gestures, and the ability to customize colors and styles. It should be easy to use from Swift, and still work in Objective C projects too.

Please make it simple to install through Swift Package Manager, CocoaPods, and Carthage if possible, and include tests where it makes sense. If you need to look up current docs or best practices, go ahead and do that.