v1.26.1

A patch release fixing three reported bugs: dual-format downloads serving the
wrong file, combined Audiobookshelf libraries dropping their ebooks on import,
and the return of the author-sync foreign-key warning burst.

Fixed

• Downloading a dual-format book now serves the format you selected
  (#1561, #1563) — the UI sends ?format=ebook|audiobook when a book has
  both formats, but the download handler never read the parameter and always
  walked its legacy path chain, so selecting Audiobook still delivered the
  epub whenever an ebook file existed. GET /api/v1/book/{id}/file now scopes
  the file selection by the requested format, using the same query-parameter
  contract the delete endpoint already had. Requests without the parameter
  keep the old behaviour, and books imported before the dual-format schema
  satisfy a format-scoped request from their single legacy path only when its
  on-disk shape matches (directory = audiobook bundle, file = ebook). Closes
  #1561.
• ABS import now picks up ebooks that Audiobookshelf marks supplementary
  (#1565, #1566) — a combined item (epub stored next to the audio files in
  one ABS library item) imported only the audiobook when the ABS library has
  "Audiobooks only" enabled: ABS then never promotes the epub to
  media.ebookFile, exposing it only as a supplementary libraryFiles entry,
  and Bindery read media.ebookFile exclusively. The normalizer now falls
  back to the supplementary ebook (preferring .epub, mirroring ABS's own
  primary-ebook selection), so both editions import — no extra API calls,
  since the expanded detail fetch already carried the data. A promoted
  primary ebook still wins. Reported in Discussion #1556 on ABS v2.35.1;
  closes #1565.
• Author catalogue sync stops mid-flight when its author is deleted
  (#1559, #1564) — the async sync runs against a snapshot of the author and
  can spend minutes fetching a prolific author's catalogue. If the row was
  deleted in that window (the Add Book orphan cleanup after a poll timeout
  where #808's direct insert didn't land, or a user deleting the author
  mid-refresh), the insert loop failed the author_id foreign-key constraint
  once per work — the reported burst logged 180 warnings for a single
  "Michael Lewis" sync. The sync now re-checks the author row after the slow
  fetch phase and aborts on a foreign-key failure whose author has vanished,
  logging a single line instead. Harmless before and after (the failed
  inserts were never persisted), but the noise made real errors easy to miss.
  Closes #1559.