batch35: add and verify test wave T1

dotnet/src/ZB.MOM.NatsNet.Server/JetStream/JetStreamClusterTypes.cs

@@ -916,6 +916,7 @@ internal sealed class JetStreamCluster
         var op = EntryOp.StreamMsgOp;
         if (!string.IsNullOrEmpty(batchId))
         {
+            body.Add(0); // reserve slot for batch op
             var batchIdLength = Math.Min(batchId.Length, ushort.MaxValue);
             body.AddRange(BitConverter.GetBytes((ushort)batchIdLength));
             body.AddRange(Encoding.ASCII.GetBytes(batchId[..batchIdLength]));