chore: Add DeepWiki badge (#9559)

README.md

@@ -34,6 +34,9 @@
   <a href="https://discord.gg/UexuTaE">
     <img alt="Chat on Discord" src="https://img.shields.io/discord/723672430744174682?color=738ad6&label=Chat%20on%20Discord&logo=discord&logoColor=ffffff&widge=false"/>
   </a>
+  <a href="https://deepwiki.com/excalidraw/excalidraw">
+    <img alt="Ask DeepWiki" src="https://deepwiki.com/badge.svg" />
+  </a>
   <a href="https://twitter.com/excalidraw">
     <img alt="Follow Excalidraw on Twitter" src="https://img.shields.io/twitter/follow/excalidraw.svg?label=follow+@excalidraw&style=social&logo=twitter"/>
   </a>