Position 1.0.0 - Swift 6

This is a major release that brings full Swift 6 support with a modern, actor-based architecture.

Highlights:
• Swift 6 language mode support
• Actor-based concurrency model
• AsyncSequence for all updates
• Modern async/await API
• Improved type safety
• No more singleton pattern

See commit message for full details of breaking changes and new features.

Update Swift tools version to 5.9 for compatibility