Tweak how McpClientTool.InvokeAsync exposes some content

Enhanced `InvokeCoreAsync` in `McpClientTool.cs` to handle non-text content by converting it to `AIContent` when possible.  This enables richer content handling for downstream `IChatClients` while maintaining fallback serialization for
unsupported cases.

Author: stephentoub

Directory.Packages.props

@@ -3,7 +3,7 @@
     <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
     <System9Version>9.0.10</System9Version>
     <System10Version>10.0.0-rc.2.25502.107</System10Version>
-    <MicrosoftExtensionsAIVersion>9.10.1</MicrosoftExtensionsAIVersion>
+    <MicrosoftExtensionsAIVersion>9.10.2</MicrosoftExtensionsAIVersion>
   </PropertyGroup>
 
   <!-- Product dependencies netstandard -->
@@ -60,7 +60,7 @@
       <PrivateAssets>all</PrivateAssets>
     </PackageVersion>
     <PackageVersion Include="GitHubActionsTestLogger" Version="2.4.1" />
-    <PackageVersion Include="Microsoft.Extensions.AI.OpenAI" Version="9.10.1-preview.1.25521.4" />
+    <PackageVersion Include="Microsoft.Extensions.AI.OpenAI" Version="9.10.2-preview.1.25552.1" />
     <PackageVersion Include="Microsoft.Extensions.DependencyInjection" Version="$(System9Version)" />
     <PackageVersion Include="Microsoft.Extensions.Hosting" Version="$(System9Version)" />
     <PackageVersion Include="Microsoft.Extensions.Logging" Version="$(System9Version)" />

src/ModelContextProtocol.Core/Client/McpClientTool.cs

@@ -91,6 +91,19 @@ internal McpClientTool(
         AIFunctionArguments arguments, CancellationToken cancellationToken)
     {
         CallToolResult result = await CallAsync(arguments, _progress, JsonSerializerOptions, cancellationToken).ConfigureAwait(false);
+
+        // If any non-text content is present, try to convert all of the contents to AIContent.
+        // If we can, return those AIContent instances instead of serializing them.
+        // This then permits richer handling of the content by downstream IChatClients.
+        if (result.Content.Any(static c => c is not TextContentBlock))
+        {
+            var aiContents = result.Content.Select(c => c.ToAIContent()).ToArray();
+            if (aiContents.All(static c => c is not null))
+            {
+                return aiContents;
+            }
+        }
+
         return JsonSerializer.SerializeToElement(result, McpJsonUtilities.JsonContext.Default.CallToolResult);
     }