new_chapters_count over-counted when scanlations share a chapter number
((manga_id, number) is non-unique, migration 0013): COUNT(*) tallied rows,
so duplicate-numbered chapters inflated the badge. Switch both the list and
per-manga read-progress queries to COUNT(DISTINCT number), and drop the dead
COALESCE (an empty set counts as 0, and the NULL-number case is handled by
the predicate). Fix the misleading comment.
Expose new_chapters_count on GET /me/read-progress/:manga_id and drive the
detail page's "N new" badge from it, instead of recomputing over the
paginated chapter list — which under-counted series past 50 chapters and
disagreed with the homepage shelf. Read markers stay client-side over the
loaded chapters and are documented as by-number (all we persist).
Adds duplicate-scanlation tests at both endpoints.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
3824eaafb2