seo: open site to search engines + expand sitemap to full catalog

- layout.tsx: flip robots.index from false→true (and the matching
  googleBot block). Drop the manual <meta name="robots"
  content="index, follow"> in the JSX head — it was duplicating
  (and conflicting with) the metadata-driven tag, so Google was
  seeing both "index, follow" AND "noindex, nofollow" and taking
  the more restrictive one. Now the metadata block is the single
  source of truth.
- sitemap.ts: expand from 5,000 articles to up to 45,000 (catalog
  is ~26k; cap leaves room for static + authors + events under
  Google's 50k-per-file ceiling). Add /authors/[slug] entries
  pulled from bb.author_profiles, and /events/[slug] entries
  pulled from bb.events. Drop the duplicate /articles/[slug]
  emissions — /news/[slug] is the canonical news URL.
- legacy-source.ts: page through the supabase query in 1,000-row
  chunks via Range headers so the 25k cap actually returns the
  full catalog (the previous `.limit(25000)` was getting silently
  truncated at PostgREST's default 1,000 max_rows).

Phase B (Ollama rewriter) is live; the press-release scrubber +
AI featured-image jobs are running in background to clean the
catalog. User explicitly chose to open SEO now rather than wait
for those jobs to finish.

src/app/layout.tsx

@@ -52,14 +52,14 @@ export const metadata: Metadata = {
     images: ['/assets/images/og-image.png']
   },
   robots: {
-    // noindex while Phase B (PR rewrite) and Phase D (i18n routes) land.
-    // Flip both to true once Google Rich Results Test passes on a sample
-    // NewsArticle and the news sitemap is wired up (Phase C).
-    index: false,
-    follow: false,
+    // Open to indexing as of 2026-05-20. Phase B (Ollama rewriter) is
+    // live; sitemap + robots.ts exist; the PR scrubber + AI featured
+    // images are running in the background to clean up the catalog.
+    index: true,
+    follow: true,
     googleBot: {
-      index: false,
-      follow: false,
+      index: true,
+      follow: true,
       'max-video-preview': -1,
       'max-image-preview': 'large',
       'max-snippet': -1
@@ -85,7 +85,8 @@ export default function RootLayout({
             or person names and offers a translate popup unprompted. */}
         <meta name="google" content="notranslate" />
         <meta httpEquiv="Content-Language" content="en" />
-        <meta name="robots" content="index, follow" />
+        {/* robots tag now driven entirely by `export const metadata.robots`
+            above — having both produced conflicting noindex/index tags. */}
 
         <script
           type="application/ld+json"