.NET: Why is AddWorkflow extension method defined on IHostApplicationBuilder interface?

I have noticed that the `AddAIAgent` extension method is defined on both the `IHostApplicationBuilder` and `IServiceCollection` interfaces, but the former simply delegates to the latter.

By contrast, `AddWorkflow` is defined only on `IHostApplicationBuilder`, even though its implementation effectively operates on `builder.Services`.

I believe that, for consistency with the rest of .NET, both methods should be defined only on `IServiceCollection`.