Artist-detail is a "pseudo-page" reachable from Library, the unified
Search page, and the global search popover. It has no [data-page]
match in the sidebar, so navigateToPage's bulk-active-removal left
every nav button unhighlighted while the user was viewing an artist —
the sidebar offered no visual anchor for where they were.
Now:
- navigateToPage('artist-detail') falls back to highlighting the
Library button when no [data-page] match exists, anchoring the
sidebar to the canonical home for artist detail views.
- A new _updateSidebarLibraryBreadcrumb() helper rewrites the Library
button label between plain "Library" and a "Library / Artist Name"
breadcrumb based on currentPage + artistDetailPageState. Long names
(>14 chars) truncate with an ellipsis; the full name shows on hover
via the title attribute.
- Called from navigateToPage (entering / leaving the page) and from
loadArtistDetailData (covers same-page artist switches in the
similar-artist chain where currentPage stays 'artist-detail').
CSS adds .nav-text-root / .nav-text-sep / .nav-text-context selectors
so the "Library" anchor word stays visually dominant while the
separator and artist name dim to a secondary tier — readable but not
competing for attention.
Pure visual change. No backend touched. No new tests (DOM-only).