[Web Assets] Add cf-mcp endpoint label (#30881)

Author: xmflsct

src/content/docs/api-shield/management-and-monitoring/endpoint-labels.mdx

@@ -56,6 +56,8 @@ Use managed labels to identify endpoints by use case. Cloudflare may automatical
 
 `cf-llm`: Services that are (partially) powered by Large Language Model (LLM).
 
+`cf-mcp`: Add this label to endpoints that implement the [Model Context Protocol (MCP)](/agents/model-context-protocol/) for AI tool and data access.
+
 `cf-rss-feed`: Add this label to endpoints that expect traffic from RSS clients.
 
 `cf-web-page`: Add this label to endpoints that serve HTML pages.