Add XML documentation across gateway, worker, and .NET client

clients/dotnet/MxGateway.Client/MxGatewayClientRetryPolicy.cs

@@ -6,8 +6,12 @@ using Polly.Retry;
 
 namespace MxGateway.Client;
 
+/// <summary>Factory and helpers for exponential-backoff retry policies on transient gRPC failures.</summary>
 internal static class MxGatewayClientRetryPolicy
 {
+    /// <summary>Creates a Polly ResiliencePipeline that retries transient gRPC failures with exponential backoff.</summary>
+    /// <param name="options">Retry configuration (max attempts, delay bounds, jitter).</param>
+    /// <param name="logger">Optional logger for retry diagnostics.</param>
     public static ResiliencePipeline Create(
         MxGatewayClientRetryOptions options,
         ILogger? logger)
@@ -36,6 +40,8 @@ internal static class MxGatewayClientRetryPolicy
             .Build();
     }
 
+    /// <summary>Returns whether a command kind is eligible for automatic retry on transient failures.</summary>
+    /// <param name="kind">The command kind to check.</param>
     public static bool IsRetryableCommand(MxCommandKind kind)
     {
         return kind is MxCommandKind.Ping