feat: add Google Search Console verification

- Create public/google73af89007ffca7c2.html for HTML file verification
- Add verification.google meta tag in layout.tsx as redundant fallback

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

app/layout.tsx

@@ -57,6 +57,9 @@ export const metadata: Metadata = {
   alternates: {
     canonical: baseUrl,
   },
+  verification: {
+    google: "73af89007ffca7c2",
+  },
 };
 
 const structuredData = {

public/google73af89007ffca7c2.html

@@ -0,0 +1 @@
+google-site-verification: google73af89007ffca7c2.html