* feat(ui): add perPageStore helper for items-per-page persistence
* feat(ui): persist items-per-page selection in localStorage
* feat(ui): enable per-page persistence on album grid, missing files and playlist tracks
* feat(ui): restore saved album grid page size on fresh load
* feat(ui): restore saved items-per-page on list load
* fix(ui): move defaultRowsPerPageOptions to perPageStore to satisfy react-refresh lint
* fix(ui): correct defaultRowsPerPageOptions import in List and add render test
* refactor(ui): default getStoredPerPage fallback to the first option
The fallback equalled options[0] at three of four call sites; default it so
those sites stop restating it. SongList and useAlbumsPerPage still pass an
explicit fallback where it legitimately differs from the first option.
* fix(ui): persist only user-selected page sizes, validate album size against width
Persisting on every pagination context value let a URL-injected perPage (e.g.
the perPage=15 album link in NowPlayingPanel) or a forced single-option mobile
grid overwrite the saved preference. Persist only a value that is an actual
option in a multi-option selector. Also validate the album grid's redux session
value against the current width so a size chosen at a wider breakpoint can't
leave an out-of-range selector.
* fix(ui): restore saved items-per-page on the radio list
RadioList passed a hard-coded perPage that overrode List's stored seed via the
props spread, so a radio-list page size was persisted but never restored. Seed
it from storage like the other list views.
* fix(ui): persist page size only on an actual selector change
Watching the pagination context value meant any valid value persisted itself:
loading a list at a breakpoint where the saved size is invalid stored the
responsive fallback, and opening a URL with a valid ?perPage= stored that too,
either way discarding the user's real preference. Inject a wrapped setPerPage
instead, so only the rows-per-page selector writes. This also drops the
option-validation heuristics, which the new trigger makes unnecessary.
