.NET: Durable Agent samples and automated validation for non-Azure Functions (#3042)

* Durable Agent samples and automated validation for non-Azure Functions

* Update test projects

* fix file encoding

* Remove AgentThreadMetadata usage

* Absorb breaking change from #3152

* Absorb newer breaking changes (AgentRunResponse --> AgentResponse)

* Absorb more breaking changes (see #3222)

* Improve integration test reliability (isolated task hubs, etc.)

* Fix flakey streaming test

---------

Co-authored-by: Mark Wallace <127216156+markwallace-microsoft@users.noreply.github.com>

dotnet/samples/DurableAgents/ConsoleApps/04_AgentOrchestration_Conditionals/Models.cs

@@ -0,0 +1,38 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System.Text.Json.Serialization;
+
+namespace AgentOrchestration_Conditionals;
+
+/// <summary>
+/// Represents an email input for spam detection and response generation.
+/// </summary>
+public sealed class Email
+{
+    [JsonPropertyName("email_id")]
+    public string EmailId { get; set; } = string.Empty;
+
+    [JsonPropertyName("email_content")]
+    public string EmailContent { get; set; } = string.Empty;
+}
+
+/// <summary>
+/// Represents the result of spam detection analysis.
+/// </summary>
+public sealed class DetectionResult
+{
+    [JsonPropertyName("is_spam")]
+    public bool IsSpam { get; set; }
+
+    [JsonPropertyName("reason")]
+    public string Reason { get; set; } = string.Empty;
+}
+
+/// <summary>
+/// Represents a generated email response.
+/// </summary>
+public sealed class EmailResponse
+{
+    [JsonPropertyName("response")]
+    public string Response { get; set; } = string.Empty;
+}