Resolve book languages stated as names ("English") to a code, so the
dialog and the server's fallback stop calling English unsupported. The
dialog groups the ebook and audiobook in a Sources card, shows
Highlighting without the Advanced disclosure, and saves a per-user
default under /user-preferences/read-aloud for books it cannot match.
Generate a synced read-aloud EPUB from a book's EPUB and audiobook through an
optional STAlign worker (Docker on CPU, or native with MLX on Apple Silicon),
with review, re-sync, replace in place, restart recovery and live progress on
the Files tab. Book details also stack the ebook and audiobook covers when
both exist. See docs/READ_ALOUD.md.
neon