SciDEX — Task: [Atlas/UI] Embeddable Top-10 open questions widget

JSON+HTML widget endpoint and [[openq:top10:]] wiki macro for embedding the per-field leaderboard with 5-min cache.

Spec File

Goal

Surface the per-field Elo leaderboards everywhere they are useful: as an
embeddable JSON+HTML widget that wiki pages, dashboards, and the per-field /science/<field> landing pages can fetch by field tag. Today the data is
queryable via field_leaderboard() in scidex/agora/open_question_tournament.py:600 but there is no public widget
endpoint or reusable HTML component that other surfaces can embed without
rewriting query+render logic.

Acceptance Criteria

☐ New endpoint GET /api/widget/open_questions/top?field=<slug>&limit=10

returns

{field, generated_at, items:[{id, question_text,
      importance_elo, rd, sub_field, source_kind, age_days, n_matches}]}

,
uses field_leaderboard() under the hood, applies the
status IN ('open','active') filter from the decay task.

☐ New endpoint GET /widget/open_questions/top.html?field=<slug>&limit=10

returns standalone embeddable HTML (≤6KB, no external JS/CSS, inline
styles). Designed to be <iframe>-able from wiki pages and from a
mermaid-fence-style code block (see Q-LIVE
q-live-embed-dashboard-in-wiki).

☐ Wiki extension: [[openq:top10:neurodegeneration]] macro in wiki

content_md is rendered server-side to the widget HTML during
wiki_quality_pipeline.py post-process. Macro syntax is documented
under docs/atlas/openq_widget.md (≤2 pages).

☐ Cache layer: widget JSON cached in Redis (or in-process LRU if Redis

unavailable) for 5 minutes, Cache-Control: public, max-age=300.

☐ Per-field landing page (api.py:56167 field-router) gains a

"Top 10 open questions" panel rendered via the new widget.

☐ Pytest: endpoint returns expected shape; HTML widget validates as

well-formed XHTML; cache is hit on the second call within 5 min;
wiki macro rewriter handles 0 results gracefully.

☐ Smoke: wiki page Alzheimer's disease shows the widget after the

pipeline runs, with at least 1 question.