.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/RecipeModels.cs

@@ -0,0 +1,43 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System.Text.Json.Serialization;
+
+namespace RecipeAssistant;
+
+// State wrapper
+internal sealed class AgentState
+{
+    [JsonPropertyName("recipe")]
+    public RecipeState Recipe { get; set; } = new();
+}
+
+// Recipe state model
+internal sealed class RecipeState
+{
+    [JsonPropertyName("title")]
+    public string Title { get; set; } = string.Empty;
+
+    [JsonPropertyName("cuisine")]
+    public string Cuisine { get; set; } = string.Empty;
+
+    [JsonPropertyName("ingredients")]
+    public List<string> Ingredients { get; set; } = [];
+
+    [JsonPropertyName("steps")]
+    public List<string> Steps { get; set; } = [];
+
+    [JsonPropertyName("prep_time_minutes")]
+    public int PrepTimeMinutes { get; set; }
+
+    [JsonPropertyName("cook_time_minutes")]
+    public int CookTimeMinutes { get; set; }
+
+    [JsonPropertyName("skill_level")]
+    public string SkillLevel { get; set; } = string.Empty;
+}
+
+// JSON serialization context
+[JsonSerializable(typeof(AgentState))]
+[JsonSerializable(typeof(RecipeState))]
+[JsonSerializable(typeof(System.Text.Json.JsonElement))]
+internal sealed partial class RecipeSerializerContext : JsonSerializerContext;