Implemented the knot node save load issues

Examples/Nodify.Calculator/GraphSerializer.cs

@@ -255,6 +255,9 @@ namespace Nodify.Calculator
                                 info.Output.Add("");
                                 info.IsFlowNode = true;
                                 break;
+                            case SystemOperations.KNOT:
+                                // Knot nodes manage their own connectors; don't add any here
+                                break;
                             default:
                                 info.Output.Add("");
                                 info.IsFlowNode = true;
@@ -414,6 +417,28 @@ namespace Nodify.Calculator
                         op.Output.Add(DeserializeConnector(sc, false));
                     }
                 }
+                else if (sysVm.SystemOperationType == SystemOperations.KNOT)
+                {
+                    // Restore knot connector shape/color/datatype from saved data
+                    if (op is KnotOperationViewModel knotOp)
+                    {
+                        knotOp.Input.Clear();
+                        knotOp.Output.Clear();
+
+                        foreach (var ic in nd.InputConnectors)
+                        {
+                            var conn = DeserializeConnector(ic, true);
+                            conn.IsKnotConnector = true;
+                            knotOp.Input.Add(conn);
+                        }
+                        foreach (var oc in nd.OutputConnectors)
+                        {
+                            var conn = DeserializeConnector(oc, false);
+                            conn.IsKnotConnector = true;
+                            knotOp.Output.Add(conn);
+                        }
+                    }
+                }
             }
         }
 
@@ -426,7 +451,8 @@ namespace Nodify.Calculator
                 ColorArgb = c.RawColor.ToArgb(),
                 DataType = c.DataType ?? string.Empty,
                 IsCopyConnector = c.IsCopyConnector,
-                IsTakeListConnector = c.IsTakeListConnector
+                IsTakeListConnector = c.IsTakeListConnector,
+                IsKnotConnector = c.IsKnotConnector
             };
         }
 
@@ -440,6 +466,7 @@ namespace Nodify.Calculator
                 DataType = cd.DataType,
                 IsCopyConnector = cd.IsCopyConnector,
                 IsTakeListConnector = cd.IsTakeListConnector,
+                IsKnotConnector = cd.IsKnotConnector,
                 IsInput = isInput
             };
         }

Examples/Nodify.Calculator/Models/SaveGraphModel.cs

@@ -53,6 +53,7 @@ namespace Nodify.Calculator.Models
         public string DataType { get; set; } = string.Empty;
         public bool IsCopyConnector { get; set; }
         public bool IsTakeListConnector { get; set; }
+        public bool IsKnotConnector { get; set; }
     }
 
     public class ConnectionData

Examples/Nodify.Calculator/Operations/OperationFactory.cs

@@ -464,6 +464,11 @@ namespace Nodify.Calculator
                         return assertOp;
                     }
 
+                    if (info.sysOp == SystemOperations.KNOT)
+                    {
+                        return new KnotOperationViewModel();
+                    }
+
                     if (info.sysOp == SystemOperations.DEBUG)
                     {
                         var debugOp = new SystemOperationViewModel