Library access roles had no effect on metadata editing: only the global Edit metadata permission
was checked, so a Viewer could edit every library they could see and an Editor could not be
limited to one library. Require Editor or Owner on the book's library for every metadata write,
including bulk edits, locks, covers, file renames, entity manager changes and author edits, and
hide the matching actions in the web client.
Keep existing access levels when an admin saves a user's library list. The old replace reset every
row to Viewer, which would now silently revoke editing on each user save.
Existing grants are Viewer, so after upgrading, admins must set Editor on each library where a
non-superuser should keep editing metadata. The released iOS app already gates editing on Editor.
Closes#1778
Expose promotion and demotion to existing superusers while keeping shared and self targets blocked. Serialize role lifecycle changes, preserve one active superuser, and invalidate stale credentials.
Closes#1208
Extract dominant color from book covers to apply ambient background tinting in BookDetailView, add cover tinting toggle to display settings, and test cover tint extraction.
neon