Merge pull request modelcontextprotocol#564 from AustinWise/patch-1

Fix C# client sample not building.

Author: jonathanhefner

docs/quickstart/client.mdx

@@ -1474,6 +1474,7 @@ Then, add the required dependencies to your project:
 dotnet add package ModelContextProtocol --prerelease
 dotnet add package Anthropic.SDK
 dotnet add package Microsoft.Extensions.Hosting
+dotnet add package Microsoft.Extensions.AI
 ```
 
 ## Setting up your API key