docs: add xml comments for Essentials routing

src/PepperDash.Essentials.Core/Routing/RouteSwitchDescriptor.cs

@@ -1,25 +1,47 @@
 namespace PepperDash.Essentials.Core
 {
     /// <summary>
-    /// Represents an individual link for a route
+    /// Represents a single switching step within a larger route, detailing the switching device, input port, and optionally the output port.
     /// </summary>
     public class RouteSwitchDescriptor
 	{
+		/// <summary>
+		/// The device performing the switch (derived from the InputPort's parent).
+		/// </summary>
 		public IRoutingInputs SwitchingDevice { get { return InputPort?.ParentDevice; } }
+		/// <summary>
+		/// The output port being switched from (relevant for matrix switchers). Null for sink devices.
+		/// </summary>
 		public RoutingOutputPort OutputPort { get; set; }
+		/// <summary>
+		/// The input port being switched to.
+		/// </summary>
 		public RoutingInputPort InputPort { get; set; }
 
+		/// <summary>
+		/// Initializes a new instance of the <see cref="RouteSwitchDescriptor"/> class for sink devices (no output port).
+		/// </summary>
+		/// <param name="inputPort">The input port being switched to.</param>
 		public RouteSwitchDescriptor(RoutingInputPort inputPort)
 		{
 			InputPort = inputPort;
 		}
 
+		/// <summary>
+		/// Initializes a new instance of the <see cref="RouteSwitchDescriptor"/> class for matrix switchers.
+		/// </summary>
+		/// <param name="outputPort">The output port being switched from.</param>
+		/// <param name="inputPort">The input port being switched to.</param>
 		public RouteSwitchDescriptor(RoutingOutputPort outputPort, RoutingInputPort inputPort)
 		{
 			InputPort = inputPort;
 			OutputPort = outputPort;
 		}
 
+		/// <summary>
+		/// Returns a string representation of the route switch descriptor.
+		/// </summary>
+		/// <returns>A string describing the switch operation.</returns>
 		public override string ToString()
 		{
             if (SwitchingDevice is IRouting)