chore: purge all rocket.new references from source

- Replace img.rocket.new mock URLs in authors/[slug] + FeaturedBento
  with /assets/images/article-placeholder.svg (live DB data drives
  these pages now; the static maps are fallback only).
- Replace broadcastb5322.builtwithrocket.new with broadcastbeat.com
  in admin API routes, news detail, forum layout, and the 4 Supabase
  edge functions that build outbound email links.
- Swap rocket-hosted JSON-LD logo URL in root layout for the local
  /assets/images/logo.png we already ship.
- Drop img.rocket.new from the Next.js image-hosts allowlist;
  add supabase.onsethost.com so storage proxy URLs can render.

The DB has had zero rocket.new image refs for weeks; this finishes
the job in the codebase so no page on broadcastbeat.com can render
a rocket-hosted asset anymore.

src/app/layout.tsx

@@ -95,7 +95,7 @@ export default function RootLayout({
               '@type': 'Organization',
               name: 'Broadcast Beat',
               url: 'https://broadcastbeat.com',
-              logo: "https://img.rocket.new/generatedImages/rocket_gen_img_1ab0c6b82-1768715893826.png",
+              logo: "https://broadcastbeat.com/assets/images/logo.png",
               description: 'The digital platform for broadcast engineering professionals. Breaking news, deep-dive features, and industry spotlights from NAB to IBC and beyond.',
               sameAs: [
               'https://linkedin.com',