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/components/bills/NewsPanel.tsx

@@ -1,9 +1,16 @@
 import { ExternalLink, Newspaper } from "lucide-react";
-import { NewsArticle } from "@/lib/types";
 import { formatDate } from "@/lib/utils";
 
+interface ArticleLike {
+  id: number;
+  source?: string;
+  headline?: string;
+  url?: string;
+  published_at?: string;
+}
+
 interface NewsPanelProps {
-  articles?: NewsArticle[];
+  articles?: ArticleLike[];
 }
 
 export function NewsPanel({ articles }: NewsPanelProps) {