Confirm-only "this post may continue this series" matcher.
- series_suggestion table (post_id, series_tag_id, score, signals jsonb, status
pending|added|dismissed, UNIQUE(post,series)); migration 0041 + two settings
knobs (series_suggest_enabled, series_suggest_threshold).
- series_match_service: weighted additive score (title-stem / same-artist /
page-continuity / shared-distinctive-tags), no single signal gating. The title
"pattern" is derived on the fly from the post titles already in a series, so it
sharpens as more are confirmed (no persisted state to drift). Candidates are
bounded to the post's artist. match_post upserts pending suggestions (UNIQUE +
on-conflict, respecting prior added/dismissed decisions).
- accept reuses add_post_as_chapter then marks 'added'; dismiss marks 'dismissed'.
- rescan_series_suggestions_task: settings-gated, time-boxed + self-resuming from
a post-id cursor (maintenance_long lane), like normalize_tags_task.
- API: GET /series/suggestions, POST .../<id>/accept|dismiss, POST .../rescan.
- Settings: enabled + threshold exposed via /settings/import.
- Tests: pure scoring helpers + matcher/accept/dismiss/rescan lifecycle + UNIQUE
dedup.
Frontend (Suggestions tab + settings card) lands next.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
