Add dynamic OG image background for social sharing (#5404)

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: kgowru

fern/docs.yml

@@ -23,6 +23,9 @@ ai-search:
       title: Fern pricing
 
 metadata:
+  og:dynamic: true
+  og:dynamic:show-url: false
+  og:dynamic:background-image: https://fern-docs.s3.us-east-2.amazonaws.com/fern-docs-og_image.png
   og:image: https://fern-docs.s3.us-east-2.amazonaws.com/fern-docs-og_image-compressed.png
   twitter:image: https://fern-docs.s3.us-east-2.amazonaws.com/fern-docs-og_image-compressed.png
   canonical-host: buildwithfern.com