[Feature]: Hotlist — surface the best content via a composite hotness score

[fatherlinux]

Parent

Child of #141 (UX 1.0: Community Platform & Personalization)

Overview

A Hotlist that surfaces the best news & events so good content stands out — not a raw chronological feed. Ranked by a composite hotness score rather than pure likes, so it's useful from day one (a brand-new like feature starts with zero likes and would otherwise be empty/cold).

Hotness score

Blend several signals into one tunable score:

• Community signal — likes ([Feature]: Like News & Events — Anonymous Like Counts #431), later saves ([Feature]: Save News & Events — Bookmark Content for Later #430). Sharpens the list as engagement accumulates.
• Freshness — recency decay so the list stays current.
• Editorial signals already computed — has_primary_image, source/trust, date_consensus_score, summary completeness.

Weights should be easy to tune (admin setting or constants). Early on, editorial + freshness carry it; likes take over as they build.

Surface

• A new tab in My Valley (Favorites / Visited / Trips / Hotlist), reusing the existing NewsItemCard / EventItemCard look.
• NOTE: a top-nav redesign is expected soon — revisit whether Hotlist deserves a more prominent home then.

Build-once ranking

The same scoring query powers #438's "most liked / hottest this week" newsletter section. Implement the hotness score once (backend service + GET /api/hotlist) and surface it both in-app (Hotlist tab) and in the newsletter.

Requirements

• Backend hotness scoring over poi_news + poi_events (published/auto_approved), windowed (e.g. rolling 2–4 weeks or "this week").
• GET /api/hotlist?window=&limit= returning ranked news + events (public).
• My Valley "Hotlist" tab rendering the ranked cards.
• Reuse in [Feature]: Watchlist-Personalized Newsletter Digest #438 for the newsletter section.

Dependencies

• Soft-requires [Feature]: Like News & Events — Anonymous Like Counts #431 (Likes) for the community signal — but degrades gracefully to editorial+freshness before likes exist.
• Feeds [Feature]: Watchlist-Personalized Newsletter Digest #438 (newsletter digest).