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/api.ts

@@ -6,6 +6,8 @@ import type {
   DashboardData,
   Follow,
   Member,
+  MemberTrendScore,
+  MemberNewsArticle,
   NewsArticle,
   PaginatedResponse,
   SettingsData,
@@ -81,6 +83,10 @@ export const membersAPI = {
     apiClient.get<Member>(`/api/members/${id}`).then((r) => r.data),
   getBills: (id: string, params?: Record<string, unknown>) =>
     apiClient.get<PaginatedResponse<Bill>>(`/api/members/${id}/bills`, { params }).then((r) => r.data),
+  getTrend: (id: string, days?: number) =>
+    apiClient.get<MemberTrendScore[]>(`/api/members/${id}/trend`, { params: { days } }).then((r) => r.data),
+  getNews: (id: string) =>
+    apiClient.get<MemberNewsArticle[]>(`/api/members/${id}/news`).then((r) => r.data),
 };
 
 // Follows