Fix Swift 6.4 Command Line Tools builds that fail because the SwiftUI macro plugin is unavailable.
- Use Apple's existing SwiftUI state property wrapper without the
@Statemacro. - Replace preview macros with
PreviewProvider. - Add state-lifecycle tests and CI builds with SwiftUI plugin discovery disabled to catch regressions.
Verified on Xcode 26.3 and Xcode 27. On Xcode 27, complete debug and release builds also passed with SwiftUI platform plugin discovery disabled.
This is a source-only release.
Full changelog: 0.9.0...0.9.1