feat(news): index news packages and research persistent events

Extract reusable literal keywords once per source revision, assign complete news packages to long-lived events, and research all event members with immutable evidence and references.

Add additive research storage, vocabulary snapshots, the two-stage workspace, isolated acceptance coverage, and a paused rollout with an initial fixed 50-news production trial.

backend/src/alphapulse/api/news.py

@@ -15,7 +15,7 @@ from alphapulse.core.db import get_session
 from alphapulse.core.redis import redis
 from alphapulse.crawler.events import NEWS_CHANNEL
 from alphapulse.models import NewsItem, NewsRevision
-from alphapulse.models.risk import ArticleAnalysis, NewsSummary, SummaryArticle
+from alphapulse.news_research.models import Package
 
 router = APIRouter(prefix="/api/news", tags=["news"], dependencies=[Depends(require_admin)])
 
@@ -120,8 +120,8 @@ async def list_news(
         conditions.append(NewsItem.id.in_(ids))
     total = await session.scalar(select(func.count()).select_from(NewsItem).where(*conditions))
     rows = (await session.execute(
-        select(NewsItem, func.left(NewsItem.content_text, EXCERPT_LENGTH).label("excerpt"), ArticleAnalysis)
-        .outerjoin(ArticleAnalysis, (ArticleAnalysis.news_id == NewsItem.id) & (ArticleAnalysis.content_hash == NewsItem.content_hash))
+        select(NewsItem, func.left(NewsItem.content_text, EXCERPT_LENGTH).label("excerpt"), Package)
+        .outerjoin(Package, (Package.news_id == NewsItem.id) & (Package.content_hash == NewsItem.content_hash))
         .where(*conditions)
         .order_by(NewsItem.published_at.desc(), NewsItem.id.desc())
         .offset((page - 1) * limit)
@@ -129,14 +129,8 @@ async def list_news(
     )).all()
 
     items = []
-    for news, excerpt, analysis in rows:
-        summaries = (await session.scalars(select(NewsSummary).join(SummaryArticle).where(
-            SummaryArticle.analysis_id == analysis.id, SummaryArticle.active.is_(True), NewsSummary.result.is_not(None)).order_by(NewsSummary.stars.desc()))).all() if analysis else []
-        risk = None
-        if analysis:
-            risk = {'state': 'pending' if analysis.state == 'done' else analysis.state}
-            if summaries:
-                risk = {**summaries[0].result, 'stars': summaries[0].stars, 'state': 'done'}
+    for news, excerpt, package in rows:
+        risk = {'state': package.state} if package else None
         items.append(NewsBrief.model_validate({**news.__dict__, 'excerpt': excerpt, 'risk': risk}))
     return success(NewsPage(items=items, total=total))