Highlights

• Package: Require Swift 6.0 toolchain (manifest stays at // swift-tools-version: 6.0; added swiftLanguageVersions: [.v6]).
• Dependency: Align swift-syntax to the Swift 6.0 line (use branch release/6.0 instead of the invalid from: "602.0.0-latest").
• CI/Local: Resolved packages and verified swift build and swift test pass locally using a temp build path.

Details

• Updated Package.swift to ensure compatibility for toolchains pinned to Swift 6.0.
• Package.resolved updated accordingly; no API changes.
• README/Docs updated to reflect Swift 6.0.