Mirrors the FavoritesPreferences pattern so the Local Library can have
a user-configurable tab order and hidden-tabs list, persisted per user
in library_preferences.db. Adds the LibraryPreferences struct, the
single-row SQLite table, the LibraryPreferencesState lifecycle, and
the V2 get/save commands.
Default order matches the current LocalLibraryView tab list with the
renamed 'folders' tab in place of the old 'albums' tab. Phase 3 will
add 'albums' (the new metadata-grouped view) to this default.
Frontend wiring lands in the next commit on this branch.
cc
vicrodh
a5ab9965d0