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/api/admin/users/route.ts

@@ -107,7 +107,7 @@ export async function POST(req: NextRequest) {
   // Send email via Supabase Edge Function
   const supabaseUrl = process.env.NEXT_PUBLIC_SUPABASE_URL;
   const supabaseAnonKey = process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY;
-  const siteUrl = process.env.NEXT_PUBLIC_SITE_URL || 'https://broadcastb5322.builtwithrocket.new';
+  const siteUrl = process.env.NEXT_PUBLIC_SITE_URL || 'https://broadcastbeat.com';
 
   try {
     const emailRes = await fetch(`${supabaseUrl}/functions/v1/send-contributor-invite`, {