Completes the multiselect rollout in LocalLibraryView and the folder/album
view:
- Select-All checkbox in the folder-album track listing, mirroring the
tracks-tab toolbar pattern.
- Shift-click anchor and ctrl-a effect for track rows in the folder-album
view.
- Cross-context mutual exclusion ("apagador") between tree-select,
album-select, track-select and the folder-album view's selection mode:
entering any context clears the others' selections and turns off their
selection mode, so two contexts cannot be active simultaneously.
The mutex is plumbed via parentSelectionActive prop + onSelectionEntered
callback between LocalLibraryView (orchestrator) and the
LocalLibraryFolderAlbumView child, matching the simpler single-switch
mental model the user requested.
cc