- Add authorClips, authorSubtitles, authorOutputType fields to appState
- Create authorClip struct for video clip management
- Implement drag-and-drop support for video clips and subtitles
- Add Settings tab with output type, region, aspect ratio options
- Create Video Clips tab with file management
- Add Subtitles tab for track management
- Prepare framework for DVD/ISO generation
- Update HandleAuthor to work with drag-and-drop system
- Add comprehensive file validation and error handling
- Support for multiple video clips compilation
- Ready for chapter detection and DVD authoring implementation
