Replace tinted modal veils with dedicated scrim tokens so dialogs, sheets, and image lightboxes dim consistently in both light and dark themes. Enforce scrim token usage in style validation to prevent backdrops that wash out in dark mode.
Keep one cover slot per medium and show the one each surface needs: the
library's shape for the face, square art on audio screens, the ebook slot
for Kobo and OPDS. Legacy covers convert on upgrade or on first read, and a
write that names no slot keeps working for released iOS builds. Also read
the dev client origin from one constant.