refactor(shared-rss): extract RSS parsing + Readability into one package

news-ingester and apps/api both shipped their own copy of rss-parser
+ jsdom + Readability glue. Single source now in packages/shared-rss.
Adds discoverFeeds (rel=alternate + common-paths probe) and validateFeed
which News Research will use. JSDOM virtualConsole is silenced once,
in the package, instead of in two parallel call sites.

- packages/shared-rss: parse, extract, discover, validate
- services/news-ingester: drop local parsers, depend on @mana/shared-rss
- apps/api: drop @mozilla/readability + jsdom direct deps, use shared

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/shared-rss/src/extract.ts

@@ -0,0 +1,47 @@
+import { Readability } from '@mozilla/readability';
+import { JSDOM, VirtualConsole } from 'jsdom';
+import { DEFAULT_USER_AGENT, type ExtractedArticle } from './types';
+
+// JSDOM's default virtualConsole rethrows CSS parse errors as
+// uncaughtException, which kills long-running services. A bare
+// VirtualConsole with no listeners swallows everything.
+const silentConsole = new VirtualConsole();
+
+export async function extractFromHtml(html: string, url: string): Promise<ExtractedArticle | null> {
+	try {
+		const dom = new JSDOM(html, { url, virtualConsole: silentConsole });
+		const article = new Readability(dom.window.document).parse();
+		if (!article || !article.textContent) return null;
+
+		const wordCount = article.textContent.split(/\s+/).filter(Boolean).length;
+		const readingTimeMinutes = Math.max(1, Math.ceil(wordCount / 200));
+
+		return {
+			title: article.title ?? null,
+			content: article.textContent,
+			htmlContent: article.content ?? '',
+			excerpt: article.excerpt || article.textContent.slice(0, 240),
+			byline: article.byline ?? null,
+			siteName: article.siteName ?? null,
+			wordCount,
+			readingTimeMinutes,
+		};
+	} catch {
+		return null;
+	}
+}
+
+export async function extractFromUrl(url: string): Promise<ExtractedArticle | null> {
+	let html: string;
+	try {
+		const response = await fetch(url, {
+			headers: { 'User-Agent': DEFAULT_USER_AGENT },
+			signal: AbortSignal.timeout(15_000),
+		});
+		if (!response.ok) return null;
+		html = await response.text();
+	} catch {
+		return null;
+	}
+	return extractFromHtml(html, url);
+}