feat(interest): add public interest tracking for members of Congress

Adds Google Trends, NewsAPI, and Google News RSS scoring for members,
mirroring the existing bill interest pipeline. Member profiles now show
a Public Interest chart (with signal breakdown) and a Related News panel.

Key changes:
- New member_trend_scores + member_news_articles tables (migration 0008)
- fetch_gnews_articles() added to news_service for unlimited RSS article storage
- Bill news fetcher now combines NewsAPI + Google News RSS (more coverage)
- New member_interest Celery worker with scheduled news + trend tasks
- GET /members/{id}/trend and /news API endpoints
- TrendChart redesigned with signal breakdown badges and bar+line combo chart
- NewsPanel accepts generic article shape (bills and members)

Co-Authored-By: Jack Levy

frontend/lib/types.ts

@@ -15,6 +15,23 @@ export interface MemberLeadership {
   current?: boolean;
 }
 
+export interface MemberTrendScore {
+  score_date: string;
+  newsapi_count: number;
+  gnews_count: number;
+  gtrends_score: number;
+  composite_score: number;
+}
+
+export interface MemberNewsArticle {
+  id: number;
+  source?: string;
+  headline?: string;
+  url?: string;
+  published_at?: string;
+  relevance_score?: number;
+}
+
 export interface Member {
   bioguide_id: string;
   name: string;
@@ -34,6 +51,7 @@ export interface Member {
   leadership_json?: MemberLeadership[];
   sponsored_count?: number;
   cosponsored_count?: number;
+  latest_trend?: MemberTrendScore;
 }
 
 export interface CitedPoint {