Add callbacks for history management to *litegraph.js*.

colour_hdri/network/resources/assets/litegraph.js/js/litegraph.js

@@ -5467,6 +5467,8 @@ LGraphNode.prototype.executeAction = function(action)
     this.onConnectingChange = null; //called before any link changes
     this.onBeforeChange = null; //called before modifying the graph
     this.onAfterChange = null; //called after modifying the graph
+    this.onBeforePaste = null; //called after copying the graph
+    this.onAfterPaste = null; //called after pasting into the graph
 
     this.connections_width = 3;
     this.round_radius = 8;
@@ -7459,6 +7461,11 @@ LGraphNode.prototype.executeAction = function(action)
 
     this.graph.beforeChange();
 
+    if (this.graph.onBeforePaste != null)
+    {
+      this.graph.onBeforePaste();
+    }
+
     //create nodes
     var clipboard_info = JSON.parse(data);
     // calculate top-left node, could work without this processing but using diff with last node pos :: clipboard_info.nodes[clipboard_info.nodes.length-1].pos
@@ -7524,6 +7531,11 @@ LGraphNode.prototype.executeAction = function(action)
     this.selectNodes(nodes);
 
     this.graph.afterChange();
+
+    if (this.graph.onAfterPaste != null)
+    {
+      this.graph.onAfterPaste();
+    }
   };
 
   /**