P0-2 + Phase A: drop Adsanity iframes, fix SEO baseline, noindex while staging

P0-2 (Adsanity iframe path removed):
- AdImage.tsx: deleted the iframe branch and the ADSANITY_CAMPAIGN_MAP
  fallback. AdImage now renders local images only; banners without a
  src render nothing.
- ads.ts: removed Ad.adsanity_id from the interface. Pruned AJA, Zixi,
  Lectrosonics, Opengear, Studio Hero, Magewell 300x250 and Blackmagic
  300x600 — they relied on ads.broadcastbeat.com which does not resolve.
  Surviving live banners: LiveU 728x90, LiveU PAYG 300x250, Telycam 300x250.
- SidebarAdStack: key no longer references the removed field.
- No banner_analytics rows reference ads.broadcastbeat.com.

Phase A (SEO baseline):
- robots.ts: fallback base URL now broadcastbeat.com (was rocket staging URL).
- sitemap.ts: fallback base URL now broadcastbeat.com (was bb-staging).
- news/[slug]/page.tsx and articles/[slug]/page.tsx: same fallback fix.
  JSON-LD now uses ISO 8601 for datePublished, absolute image URL via
  SITE_URL prefix, and publisher.logo points at /assets/images/logo.png
  instead of the 404-ing /legacy/site/broadcastbeat-logo.png.
- layout.tsx: removed the /en /es /pt /fr /de /zh /ja /ar /hi hreflang
  alternates - those routes 404 today; Phase D will reinstate. Replaced
  rocket.new Organization schema URL with broadcastbeat.com. Set
  robots index/follow=false until Phase B-D land and Rich Results passes.

Featured-image fallback hardening:
- legacy-source: rowToArticle now treats BB_Gray, no_image and placeholder
  URLs as null and falls back to the new placeholder so dead images do not
  leak through to the page.
- public/assets/images/article-placeholder.svg: new clean dark gradient
  with BroadcastBeat wordmark, NOT no_image.png style.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/app/articles/[slug]/page.tsx

@@ -16,7 +16,19 @@ interface PageProps {
 }
 
 const SITE_URL =
-  process.env.NEXT_PUBLIC_SITE_URL || "https://bb-staging.onsethost.com";
+  process.env.NEXT_PUBLIC_SITE_URL || "https://broadcastbeat.com";
+
+function toIso(d: string | null | undefined): string {
+  if (!d) return new Date().toISOString();
+  const parsed = new Date(d);
+  return isNaN(parsed.getTime()) ? new Date().toISOString() : parsed.toISOString();
+}
+
+function absoluteImage(src: string | undefined | null): string {
+  if (!src) return `${SITE_URL}/assets/images/article-placeholder.jpg`;
+  if (/^https?:\/\//i.test(src)) return src;
+  return `${SITE_URL}${src.startsWith("/") ? "" : "/"}${src}`;
+}
 
 async function loadArticle(slug: string): Promise<{
   article: Article | null;
@@ -77,15 +89,16 @@ export default async function ArticlePage({ params }: PageProps) {
     "@type": "Article",
     headline: article.title,
     description: article.excerpt,
-    image: article.image,
+    image: [absoluteImage(article.image)],
     author: { "@type": "Person", name: article.author },
     publisher: {
       "@type": "Organization",
       name: "BroadcastBeat",
-      logo: { "@type": "ImageObject", url: `${SITE_URL}/legacy/site/broadcastbeat-logo.png` },
+      logo: { "@type": "ImageObject", url: `${SITE_URL}/assets/images/logo.png` },
     },
-    datePublished: article.date,
+    datePublished: toIso(article.date),
     dateModified: new Date().toISOString(),
+    mainEntityOfPage: { "@type": "WebPage", "@id": `${SITE_URL}/articles/${article.slug}` },
   };
 
   return (