.NET: [BREAKING] Implement Polymorphic Routing (#3792)

* feat: Implement Polymorphic Routing

* feat: Add support for Send/Yield annotations with basic Executor

* Adds annotations to Declarative workflow executors

* fix: Address PR Comments

* Implicit filter in collection loops
* Remove debug / usused / superfluous code
* Fix ProtocolBuilder implicit output registrations
* Fix logic error in ExecuteRouteGeneratorTests.ClassWithManualConfigureProtocol_DoesNotGenerate

* fix: Solidify type checks and send/yield type registrations

* fix: Suppress generation of TurnTokens out of AggregateTurnMessagesExecutor

* Fixes an issue where ConcurrentEndExecutor is not expecting TurnTokens.

* fix: Add ProtocolBuilder support for chained-delegation

* Updates Declarative pacakge to rely on chained-delegation Send/Yield registration
* Renames DeclarativeActionExectuor's new ExecuteAsync to ExecuteActionAsync to avoid colliding with Executor.ExecutoeAsync

* fix: Address PR Comments

* Fixes type mapping in FanInEdgeRunner
* Fixes and expalins send/yield type registration in FunctionExecutor

* fixup: build-break

* fix: Add missing SendsMesage declaration to InvokeAzureAgentExecutor

dotnet/src/Microsoft.Agents.AI.Workflows.Declarative/ObjectModel/InvokeFunctionToolExecutor.cs

@@ -49,6 +49,7 @@ internal sealed class InvokeFunctionToolExecutor(
     protected override bool IsDiscreteAction => false;
 
     /// <inheritdoc/>
+    [SendsMessage(typeof(ExternalInputRequest))]
     protected override async ValueTask<object?> ExecuteAsync(IWorkflowContext context, CancellationToken cancellationToken = default)
     {
         string functionName = this.GetFunctionName();