Add particle animation for connection activity

tp-flow-nodes.js

@@ -98,21 +98,21 @@ export class TpFlowNodes extends zoom(panning(connections(LitElement))) {
     this.connections = [];
     
     // Create all nodes first
-    const nodes = flowData.nodes.map(nodeData => {
+    const nodes = flowData.nodes?.map(nodeData => {
       const node = this.createNode(nodeData.type);
       node.importData(nodeData);
       return node;
     });
   
     // Set nodes and wait for render
-    this.nodes = nodes;
+    this.nodes = nodes || [];
     await this.updateComplete;
   
     // Wait for all nodes to be ready
     await Promise.all(this.nodes.map(node => node.updateComplete));
     
     // Only after nodes are ready, restore connections
-    this.connections = flowData.connections;
+    this.connections = flowData.connections || [];
   
     // Restore canvas state
     if (flowData.canvas) {