.NET: AG-UI Docs samples (#2194)

* Add AG-UI Blazor sample

* Add AG-UI getting started samples

* Cleanups

* Update the dojo samples

* cleanups

* Fix readme

* Address feedback and further cleanups

* Fix build

* Missing fixes

dotnet/samples/GettingStarted/AGUI/Step05_StateManagement/Server/Program.cs

@@ -0,0 +1,59 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using Azure.AI.OpenAI;
+using Azure.Identity;
+using Microsoft.Agents.AI;
+using Microsoft.Agents.AI.Hosting.AGUI.AspNetCore;
+using Microsoft.Extensions.AI;
+using Microsoft.Extensions.Options;
+using OpenAI.Chat;
+using RecipeAssistant;
+
+WebApplicationBuilder builder = WebApplication.CreateBuilder(args);
+builder.Services.AddHttpClient().AddLogging();
+builder.Services.ConfigureHttpJsonOptions(options =>
+    options.SerializerOptions.TypeInfoResolverChain.Add(RecipeSerializerContext.Default));
+builder.Services.AddAGUI();
+
+// Configure to listen on port 8888
+builder.WebHost.UseUrls("http://localhost:8888");
+
+WebApplication app = builder.Build();
+
+string endpoint = builder.Configuration["AZURE_OPENAI_ENDPOINT"]
+    ?? throw new InvalidOperationException("AZURE_OPENAI_ENDPOINT is not set.");
+string deploymentName = builder.Configuration["AZURE_OPENAI_DEPLOYMENT_NAME"]
+    ?? throw new InvalidOperationException("AZURE_OPENAI_DEPLOYMENT_NAME is not set.");
+
+// Get JsonSerializerOptions
+var jsonOptions = app.Services.GetRequiredService<IOptions<Microsoft.AspNetCore.Http.Json.JsonOptions>>().Value;
+
+// Create base agent
+ChatClient chatClient = new AzureOpenAIClient(
+        new Uri(endpoint),
+        new DefaultAzureCredential())
+    .GetChatClient(deploymentName);
+
+AIAgent baseAgent = chatClient.AsIChatClient().CreateAIAgent(
+    name: "RecipeAgent",
+    instructions: """
+        You are a helpful recipe assistant. When users ask you to create or suggest a recipe,
+        respond with a complete AgentState JSON object that includes:
+        - recipe.title: The recipe name
+        - recipe.cuisine: Type of cuisine (e.g., Italian, Mexican, Japanese)
+        - recipe.ingredients: Array of ingredient strings with quantities
+        - recipe.steps: Array of cooking instruction strings
+        - recipe.prep_time_minutes: Preparation time in minutes
+        - recipe.cook_time_minutes: Cooking time in minutes
+        - recipe.skill_level: One of "beginner", "intermediate", or "advanced"
+
+        Always include all fields in the response. Be creative and helpful.
+        """);
+
+// Wrap with state management middleware
+AIAgent agent = new SharedStateAgent(baseAgent, jsonOptions.SerializerOptions);
+
+// Map the AG-UI agent endpoint
+app.MapAGUI("/", agent);
+
+await app.RunAsync();