Add ability to fully clear cached online library by deleting and recreating the database file.
Integrate new Clear Cache option in settings UI, which restarts the app after clearing.
Remove unused artist/album fields from cache and UI. Add process plugin for relaunch.
Add UI and logic to select music and playlists folders in settings using
tauri dialog plugin. Integrate @tauri-apps/plugin-dialog, plugin-fs, and
plugin-store in both frontend and backend. Update capabilities and
dependencies to support new plugins. Improve settings page with folder
selectors and info note for better user experience.
