Add unit tests for Router configuration and transport layers

- Implemented tests for RouterConfig, RoutingOptions, StaticInstanceConfig, and RouterConfigOptions to ensure default values are set correctly.
- Added tests for RouterConfigProvider to validate configurations and ensure defaults are returned when no file is specified.
- Created tests for ConfigValidationResult to check success and error scenarios.
- Developed tests for ServiceCollectionExtensions to verify service registration for RouterConfig.
- Introduced UdpTransportTests to validate serialization, connection, request-response, and error handling in UDP transport.
- Added scripts for signing authority gaps and hashing DevPortal SDK snippets.

src/__Libraries/StellaOps.Router.Transport.InMemory/InMemoryTransportClient.cs

@@ -5,6 +5,7 @@ using Microsoft.Extensions.Options;
 using StellaOps.Router.Common.Abstractions;
 using StellaOps.Router.Common.Enums;
 using StellaOps.Router.Common.Models;
+using static StellaOps.Router.Common.Models.CancelReasons;
 
 namespace StellaOps.Router.Transport.InMemory;
 
@@ -12,12 +13,13 @@ namespace StellaOps.Router.Transport.InMemory;
 /// In-memory transport client implementation for testing and development.
 /// Used by the Microservice SDK to send frames to the Gateway.
 /// </summary>
-public sealed class InMemoryTransportClient : ITransportClient, IDisposable
+public sealed class InMemoryTransportClient : ITransportClient, IMicroserviceTransport, IDisposable
 {
     private readonly InMemoryConnectionRegistry _registry;
     private readonly InMemoryTransportOptions _options;
     private readonly ILogger<InMemoryTransportClient> _logger;
     private readonly ConcurrentDictionary<string, TaskCompletionSource<Frame>> _pendingRequests = new();
+    private readonly ConcurrentDictionary<string, CancellationTokenSource> _inflightHandlers = new();
     private readonly CancellationTokenSource _clientCts = new();
     private bool _disposed;
     private string? _connectionId;
@@ -172,29 +174,54 @@ public sealed class InMemoryTransportClient : ITransportClient, IDisposable
             return;
         }
 
+        var correlationId = frame.CorrelationId ?? Guid.NewGuid().ToString("N");
+
+        // Create a linked CancellationTokenSource for this handler
+        // This allows cancellation via CANCEL frame or transport shutdown
+        using var handlerCts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
+        _inflightHandlers[correlationId] = handlerCts;
+
         try
         {
-            var response = await OnRequestReceived(frame, cancellationToken);
+            var response = await OnRequestReceived(frame, handlerCts.Token);
 
             // Ensure response has same correlation ID
-            var responseFrame = response with { CorrelationId = frame.CorrelationId };
-            await channel.ToGateway.Writer.WriteAsync(responseFrame, cancellationToken);
+            var responseFrame = response with { CorrelationId = correlationId };
+
+            // Only send response if not cancelled
+            if (!handlerCts.Token.IsCancellationRequested)
+            {
+                await channel.ToGateway.Writer.WriteAsync(responseFrame, cancellationToken);
+            }
+            else
+            {
+                _logger.LogDebug("Not sending response for cancelled request {CorrelationId}", correlationId);
+            }
         }
         catch (OperationCanceledException)
         {
-            _logger.LogDebug("Request {CorrelationId} was cancelled", frame.CorrelationId);
+            _logger.LogDebug("Request {CorrelationId} was cancelled", correlationId);
         }
         catch (Exception ex)
         {
-            _logger.LogError(ex, "Error handling request {CorrelationId}", frame.CorrelationId);
-            // Send error response
-            var errorFrame = new Frame
+            _logger.LogError(ex, "Error handling request {CorrelationId}", correlationId);
+
+            // Only send error response if not cancelled
+            if (!handlerCts.Token.IsCancellationRequested)
             {
-                Type = FrameType.Response,
-                CorrelationId = frame.CorrelationId,
-                Payload = ReadOnlyMemory<byte>.Empty
-            };
-            await channel.ToGateway.Writer.WriteAsync(errorFrame, cancellationToken);
+                var errorFrame = new Frame
+                {
+                    Type = FrameType.Response,
+                    CorrelationId = correlationId,
+                    Payload = ReadOnlyMemory<byte>.Empty
+                };
+                await channel.ToGateway.Writer.WriteAsync(errorFrame, cancellationToken);
+            }
+        }
+        finally
+        {
+            // Remove from inflight tracking
+            _inflightHandlers.TryRemove(correlationId, out _);
         }
     }
 
@@ -204,13 +231,27 @@ public sealed class InMemoryTransportClient : ITransportClient, IDisposable
 
         _logger.LogDebug("Received CANCEL for correlation {CorrelationId}", frame.CorrelationId);
 
+        // Cancel the inflight handler via its CancellationTokenSource
+        if (_inflightHandlers.TryGetValue(frame.CorrelationId, out var handlerCts))
+        {
+            try
+            {
+                handlerCts.Cancel();
+                _logger.LogInformation("Cancelled handler for request {CorrelationId}", frame.CorrelationId);
+            }
+            catch (ObjectDisposedException)
+            {
+                // Handler already completed
+            }
+        }
+
         // Complete any pending request with cancellation
         if (_pendingRequests.TryRemove(frame.CorrelationId, out var tcs))
         {
             tcs.TrySetCanceled();
         }
 
-        // Notify handler
+        // Notify external handler (for custom cancellation logic)
         if (OnCancelReceived is not null && Guid.TryParse(frame.CorrelationId, out var correlationGuid))
         {
             _ = OnCancelReceived(correlationGuid, null);
@@ -381,6 +422,33 @@ public sealed class InMemoryTransportClient : ITransportClient, IDisposable
         await channel.ToGateway.Writer.WriteAsync(frame, cancellationToken);
     }
 
+    /// <summary>
+    /// Cancels all in-flight handler requests.
+    /// Called when connection is closed or transport is shutting down.
+    /// </summary>
+    /// <param name="reason">The reason for cancellation.</param>
+    public void CancelAllInflight(string reason)
+    {
+        var count = 0;
+        foreach (var kvp in _inflightHandlers)
+        {
+            try
+            {
+                kvp.Value.Cancel();
+                count++;
+            }
+            catch (ObjectDisposedException)
+            {
+                // Already completed/disposed
+            }
+        }
+
+        if (count > 0)
+        {
+            _logger.LogInformation("Cancelled {Count} in-flight handlers: {Reason}", count, reason);
+        }
+    }
+
     /// <summary>
     /// Disconnects from the transport.
     /// </summary>
@@ -388,6 +456,9 @@ public sealed class InMemoryTransportClient : ITransportClient, IDisposable
     {
         if (_connectionId is null) return;
 
+        // Cancel all inflight handlers before disconnecting
+        CancelAllInflight(CancelReasons.Shutdown);
+
         await _clientCts.CancelAsync();
 
         if (_receiveTask is not null)
@@ -407,6 +478,9 @@ public sealed class InMemoryTransportClient : ITransportClient, IDisposable
         if (_disposed) return;
         _disposed = true;
 
+        // Cancel all inflight handlers
+        CancelAllInflight(Shutdown);
+
         _clientCts.Cancel();
 
         foreach (var tcs in _pendingRequests.Values)
@@ -414,6 +488,7 @@ public sealed class InMemoryTransportClient : ITransportClient, IDisposable
             tcs.TrySetCanceled();
         }
         _pendingRequests.Clear();
+        _inflightHandlers.Clear();
 
         if (_connectionId is not null)
         {

src/__Libraries/StellaOps.Router.Transport.InMemory/ServiceCollectionExtensions.cs

@@ -35,6 +35,7 @@ public static class ServiceCollectionExtensions
         // Register interfaces
         services.TryAddSingleton<ITransportServer>(sp => sp.GetRequiredService<InMemoryTransportServer>());
         services.TryAddSingleton<ITransportClient>(sp => sp.GetRequiredService<InMemoryTransportClient>());
+        services.TryAddSingleton<IMicroserviceTransport>(sp => sp.GetRequiredService<InMemoryTransportClient>());
 
         return services;
     }
@@ -81,6 +82,7 @@ public static class ServiceCollectionExtensions
         services.TryAddSingleton<InMemoryConnectionRegistry>();
         services.TryAddSingleton<InMemoryTransportClient>();
         services.TryAddSingleton<ITransportClient>(sp => sp.GetRequiredService<InMemoryTransportClient>());
+        services.TryAddSingleton<IMicroserviceTransport>(sp => sp.GetRequiredService<InMemoryTransportClient>());
 
         return services;
     }