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.Common/Abstractions/IGlobalRoutingState.cs

@@ -7,6 +7,38 @@ namespace StellaOps.Router.Common.Abstractions;
 /// </summary>
 public interface IGlobalRoutingState
 {
+    /// <summary>
+    /// Adds a connection to the routing state.
+    /// </summary>
+    /// <param name="connection">The connection state to add.</param>
+    void AddConnection(ConnectionState connection);
+
+    /// <summary>
+    /// Removes a connection from the routing state.
+    /// </summary>
+    /// <param name="connectionId">The connection ID to remove.</param>
+    void RemoveConnection(string connectionId);
+
+    /// <summary>
+    /// Updates an existing connection's state.
+    /// </summary>
+    /// <param name="connectionId">The connection ID to update.</param>
+    /// <param name="update">The update action to apply.</param>
+    void UpdateConnection(string connectionId, Action<ConnectionState> update);
+
+    /// <summary>
+    /// Gets a connection by its ID.
+    /// </summary>
+    /// <param name="connectionId">The connection ID.</param>
+    /// <returns>The connection state, or null if not found.</returns>
+    ConnectionState? GetConnection(string connectionId);
+
+    /// <summary>
+    /// Gets all active connections.
+    /// </summary>
+    /// <returns>All active connections.</returns>
+    IReadOnlyList<ConnectionState> GetAllConnections();
+
     /// <summary>
     /// Resolves an HTTP request to an endpoint descriptor.
     /// </summary>

src/__Libraries/StellaOps.Router.Common/Abstractions/IMicroserviceTransport.cs

@@ -0,0 +1,43 @@
+using StellaOps.Router.Common.Models;
+
+namespace StellaOps.Router.Common.Abstractions;
+
+/// <summary>
+/// Represents a transport connection from a microservice to the gateway.
+/// This interface is used by the Microservice SDK to communicate with the router.
+/// </summary>
+public interface IMicroserviceTransport
+{
+    /// <summary>
+    /// Connects to the router and registers the microservice.
+    /// </summary>
+    /// <param name="instance">The instance descriptor.</param>
+    /// <param name="endpoints">The endpoints to register.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    Task ConnectAsync(
+        InstanceDescriptor instance,
+        IReadOnlyList<EndpointDescriptor> endpoints,
+        CancellationToken cancellationToken);
+
+    /// <summary>
+    /// Disconnects from the router.
+    /// </summary>
+    Task DisconnectAsync();
+
+    /// <summary>
+    /// Sends a heartbeat to the router.
+    /// </summary>
+    /// <param name="heartbeat">The heartbeat payload.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    Task SendHeartbeatAsync(HeartbeatPayload heartbeat, CancellationToken cancellationToken);
+
+    /// <summary>
+    /// Event raised when a REQUEST frame is received from the gateway.
+    /// </summary>
+    event Func<Frame, CancellationToken, Task<Frame>>? OnRequestReceived;
+
+    /// <summary>
+    /// Event raised when a CANCEL frame is received from the gateway.
+    /// </summary>
+    event Func<Guid, string?, Task>? OnCancelReceived;
+}