After a successful bookmark insert, the create handler spawns a
detached tokio task that calls pipeline::enqueue_pending_for_manga
for every chapter of the manga where page_count = 0 and the source
row is not dropped. Bookmark create returns 201 immediately; enqueue
work happens in the background and its failure is logged without
surfacing to the user (the daily cron sweeps anything missed).
The Phase A dedup index handles re-bookmarks idempotently — deleting
and recreating a bookmark does not duplicate in-flight jobs — and the
Phase B worker pool drains them.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>