styled-components 6.4 now available

There's a lot of great stuff in this release! In no particular order:

- RSC implementation promoted from experimental - More intelligent caching + real algorithmic speed improvements (up to 3.5x depending on workload) - React Native improvements (css-to-react-native v4 now supported via peer when it's out) - Updated cross-framework CSP support - A seamless Client/RSC theme system via new createTheme() API - attrs() typing improvements and other quality-of-life changes

Feedback welcome, especially ideas for the next major. Documentation website refresh coming later this week!