Implement InMemory Transport Layer for StellaOps Router

- Added InMemoryTransportOptions class for configuration settings including timeouts and latency.
- Developed InMemoryTransportServer class to handle connections, frame processing, and event management.
- Created ServiceCollectionExtensions for easy registration of InMemory transport services.
- Established project structure and dependencies for InMemory transport library.
- Implemented comprehensive unit tests for endpoint discovery, connection management, request/response flow, and streaming capabilities.
- Ensured proper handling of cancellation, heartbeat, and hello frames within the transport layer.

src/__Libraries/StellaOps.Microservice/IRouterConnectionManager.cs

@@ -0,0 +1,26 @@
+using StellaOps.Router.Common.Models;
+
+namespace StellaOps.Microservice;
+
+/// <summary>
+/// Manages connections to router gateways.
+/// </summary>
+public interface IRouterConnectionManager
+{
+    /// <summary>
+    /// Gets the current connection states.
+    /// </summary>
+    IReadOnlyList<ConnectionState> Connections { get; }
+
+    /// <summary>
+    /// Starts the connection manager.
+    /// </summary>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    Task StartAsync(CancellationToken cancellationToken);
+
+    /// <summary>
+    /// Stops the connection manager.
+    /// </summary>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    Task StopAsync(CancellationToken cancellationToken);
+}