Include a list of trees that pairs with parsed frames

These can be viewed as pairs: for each frame, there is the full workflow tree that is slowly built up with the new nodes.

Add a copy method onto Node class to store a current copy of the workflow tree.

Author: wenli-cai

workflow-trace-viewer/src/jvmMain/kotlin/com/squareup/workflow1/traceviewer/model/Node.kt

@@ -9,15 +9,26 @@ package com.squareup.workflow1.traceviewer.model
  */
 public class Node(
   val name: String,
-  val id: String,
   val parent: String,
-  val parentId: String,
   val props: Any? = null,
   val state: Any? = null,
   val renderings: Any? = null,
-  val children: List<Node>,
+  val children: MutableList<Node>,
+  val id: String
 ) {
 
+  fun copy(): Node {
+    return Node(
+      name = name,
+      parent = parent,
+      props = props,
+      state = state,
+      rendering = rendering,
+      children = children.map { it.copy() }.toMutableList(),
+      id = id
+    )
+  }
+
   override fun toString(): String {
     return "Node(name='$name', parent='$parent', children=${children})"
   }

workflow-trace-viewer/src/jvmMain/kotlin/com/squareup/workflow1/traceviewer/ui/WorkflowInfoPanel.kt

@@ -94,9 +94,9 @@ private fun NodePanelDetails(
     val fields = mapOf(
       "Name" to node.name,
       "ID" to node.id,
-      "Props" to node.props.toString(),
-      "State" to node.state.toString(),
-      "Renderings" to node.renderings.toString()
+      "Props" to node.props,
+      "State" to node.state,
+      "Rendering" to node.rendering
     )
 
     fields.forEach { (label, value) ->