Public listing of claimed publishers with subscription counts + most-recent article. Drives the /discover/newsletters listener- acquisition page. Excludes publishers who haven't claimed (no subscriptions enabled / no payout configured) so the directory only surfaces real wired-up authors.

Optional vertical filter (tech | health | young_moms | yoga | science | finance | news) restricts to publishers tagged with that taxonomy slug. See app/vertical_classifier.py for the canonical list.

2026-06-14 · architectural rewrite (closes #562). Reads from the mv_discover_newsletters_snapshot materialized view (migration 0153) — a single indexed SELECT replaces the four queries + Python-side fan-out that took 50+s on cold cache. The MV is refreshed every 5 minutes by the separate worker (separate PR); stale data is fine because publisher claims are rare events.

SQLite path (tests/dev): the materialized view doesn't exist — fall back to the legacy Python fan-out so tests keep working.