model tree fix

src/client/viewer/main.ts

@@ -286,7 +286,12 @@ async function loadStepGeometry(): Promise<void> {
   fitCamera(group)
   addGrid(group)
 
-  if (data.tree) wireTreePanel(data.tree)
+  const treeContent = document.getElementById('tree-content')
+  if (data.tree) {
+    wireTreePanel(data.tree)
+  } else if (treeContent) {
+    treeContent.innerHTML = '<p class="text-xs text-gray-500 px-4 py-3">Tree unavailable — reconvert this model in the admin panel to enable.</p>'
+  }
 }
 
 // ---- STL loader (client-side, Three.js built-in) -------------------------
@@ -407,31 +412,34 @@ function wireTreePanel(root: HierarchyNode) {
   const content = document.getElementById('tree-content')
   if (!content) return
 
-  // Skip an unnamed single-child root wrapper — go straight to its children
+  // Skip an unnamed root wrapper — go straight to its children
   const topNodes = (!root.name && root.children.length > 0) ? root.children : [root]
 
   content.innerHTML = ''
   for (const node of topNodes) {
     content.append(buildTreeNode(node, 0))
   }
-
-  // Wire tree toggle button
-  const treePanel  = document.getElementById('tree-panel')!
-  const toggleBtn  = document.getElementById('tree-toggle-btn')
-  const closeBtn   = document.getElementById('tree-close-btn')
-
-  const openPanel  = () => { treePanel.classList.remove('closed'); toggleBtn?.classList.add('text-accent') }
-  const closePanel = () => { treePanel.classList.add('closed');    toggleBtn?.classList.remove('text-accent') }
-
-  toggleBtn?.addEventListener('click', () =>
-    treePanel.classList.contains('closed') ? openPanel() : closePanel()
-  )
-  closeBtn?.addEventListener('click', closePanel)
 }
 
 // ---- Viewer toolbar ------------------------------------------------------
 
 function wireToolbar() {
+  // Model tree panel toggle (always wired; content populated after geometry loads)
+  const treePanel = document.getElementById('tree-panel')
+  const treeBtn   = document.getElementById('tree-toggle-btn')
+  const treeClose = document.getElementById('tree-close-btn')
+  if (treePanel) {
+    treeBtn?.addEventListener('click', () => {
+      const closing = !treePanel.classList.contains('closed')
+      treePanel.classList.toggle('closed')
+      treeBtn.classList.toggle('text-accent', !closing)
+    })
+    treeClose?.addEventListener('click', () => {
+      treePanel.classList.add('closed')
+      treeBtn?.classList.remove('text-accent')
+    })
+  }
+
   // Copy-link
   const copyBtn = document.getElementById('copy-link-btn') as HTMLButtonElement | null
   if (copyBtn) {