List new ref arch diagram on the by-solution page

Author: RebeccaTamachiro

src/content/docs/reference-architecture/by-solution.mdx

@@ -80,6 +80,10 @@ Content related to DNS, caching, load balancing and other Cloudflare services de
 - [Content Delivery Network](/reference-architecture/architectures/cdn/)
 - [Load Balancing](/reference-architecture/architectures/load-balancing/)
 
+#### Reference architecture diagrams
+
+- [Designing a distributed web performance architecture](/reference-architecture/diagrams/content-delivery/distributed-web-performance-architecture/)
+
 ### Application Security
 
 Content related to protecting your applications from threats such as DDoS attack, SQL injection, exploiting application vulnerabilities, scraping API data and more.