Cross-vertical trending: recent published persona briefings grouped by vertical + most-active source publishers in the last 24h + the top individual articles ranked by trending_score + the most recent daily-brief compilation as featured + the last 7 daily briefs as recent_daily_briefs.

Performance layout (post-2026-06-04): Q1 — briefings/by_vertical: still computed inline (cheap, ORDER BY + LIMIT over persona_briefings; sub-100ms). Q2 — active_publishers_24h: reads from trending_publisher_snapshot (migration 0135) which is UPSERTed every ~5 min by TrendingSnapshotWorker. This replaces the GROUP BY over 20K+ is_quality=True articles that was running ~9.9s wall-clock on cold calls. Q3 — top_articles (NEW 2026-06-04; window widened 24h → 7d 2026-06-04 + always-10 fallback): ORDER BY trending_score DESC NULLS LAST over the last 7 days of quality articles. Originally mirrored daily_brief_worker.py:825 (24h window) but operator-flagged that the prior days' content must remain discoverable — especially during LLM-provider outages that strand most of the day's articles without a summary. A relaxed fallback pass fires when the strict list is shorter than 10, dropping the trending_score IS NOT NULL filter and ordering by created_at DESC to fill the gap, so the surface is always populated when any quality article exists in the window. Excludes slug LIKE 'daily-brief-%' in both passes so the compilation is featured separately and not double-billed. Q4 — featured (NEW 2026-06-04): the latest rendered daily-brief-YYYY-MM-DD article — the same article whose audio is published to the storyflo · trending Spotify show. Listeners now see it inside the in-app feed too. Q5 — recent_daily_briefs (NEW 2026-06-04): the last 7 rendered daily-brief compilations ordered by created_at DESC. Acts as an always-populated anchor section for the trending UI even when top_articles is sparse — listeners can always scroll back to "yesterday's top 10". Only daily briefs with a done RenderJob (rendered audio available) appear; an unrendered brief is a dead row to a listener expecting playback to start on click.

The in-process 60s TTL cache (app/trending_cache.py) stays as a second-line defence — cache key now includes top so different callers share rows but don't collide.

Snapshot freshness contract: TrendingSnapshotWorker is the primary driver (5-min loop); cron_extra_ticks.trending_snapshot_tick on the daily-brief loop is the safety-net. The worker fires its first tick immediately on start so the snapshot row exists within seconds of deploy. If the row is somehow missing, this endpoint returns [] for active_publishers_24h rather than falling back to the 9.9s aggregation.