Save tree state

template/app/components/TreeNode.vue

@@ -1,14 +1,14 @@
 <script setup>
-import { ref } from 'vue'
+import { useTreeState } from '~/composables/useTreeState'
 
 defineProps({ nodes: Array, depth: { type: Number, default: 0 } })
 
 const router = useRouter()
-const collapsed = ref({})
+const { collapsed } = useTreeState()   // ← shared state, not local ref
 
 function getTitle(node) {
-  if (node.title == "index") return "Index"
-  return node.title || node._path?.split('/').pop() || 'Home';
+  if (node.title === 'index') return 'Index'
+  return node.title || node._path?.split('/').pop() || 'Home'
 }
 
 function navigate(path) {