Add similarweb-analytics Docker sandbox skill

similarweb-analytics/agents/openai.yaml

@@ -0,0 +1,4 @@
+interface:
+  display_name: "SimilarWeb Analytics"
+  short_description: "Analyze domains with SimilarWeb in a Docker sandbox"
+  default_prompt: "Analyze traffic, rank, sources, and geography for a domain using Dockerized SimilarWeb workflow."