fix: pass locale explicitly to Hero and force-dynamic on locale-sensitive API routes

- Hero.tsx: pass locale prop directly to getTranslations instead of
  relying on setRequestLocale async storage, which can be lost during
  Next.js RSC streaming
- book-reviews route: replace revalidate=300 with force-dynamic to
  prevent cached English responses being served to German locale requests
- content/page route: add runtime=nodejs and force-dynamic (was missing
  both, violating CLAUDE.md API route conventions)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/api/content/page/route.ts

@@ -3,6 +3,9 @@ import { getContentByKey } from "@/lib/content";
 import { getContentPage } from "@/lib/directus";
 import { richTextToSafeHtml } from "@/lib/richtext";
 
+export const runtime = 'nodejs';
+export const dynamic = 'force-dynamic';
+
 const CACHE_TTL = 300; // 5 minutes
 
 export async function GET(request: NextRequest) {