update insights docs to include summary and higlighted traces feature

src/langsmith/insights.mdx

@@ -85,6 +85,15 @@ You can drill down through categories and subcategories to view the underlying t
 
 <Frame caption="Common topics of conversations with the https://chat.langchain.com chatbot"><img src="/langsmith/images/insights-nav.gif" /> </Frame>
 
+### Executive summary
+At the top of each report, you'll find an executive summary that surfaces the most important patterns discovered in your traces. This includes:
+
+- Key findings with percentages showing how often each pattern appears.
+- Clickable references (e.g., #1, #2, #3) to traces the agent identified as exceptionally relevant to your question.
+
+<Frame caption="Executive summary showing key patterns with trace references"><img src="/langsmith/images/insights-summary.png" /> </Frame>
+
+
 ### Top-level categories
 Your traces are automatically grouped into top-level categories that represent the broadest patterns in your data.