DJ USB Tkit 0.1.0

• Initial public release.
• Local-first library scanning, playlist management, native playback, and
  frontend source-folder workflows.
• USB import/export with mirror and additive playlist sync modes.
• USB diagnostics, strict parity reporting, preview-first repair actions, and
  timestamped database backups before write operations.
• Local BPM, key, waveform, and artwork analysis for export preparation.
• Release packaging workflow for Tauri desktop builds.