fix: resolve lint errors in NodeEditorPanel and useTreeLayout

- Fix unused 'children' destructuring with _children prefix
- Move handleClose declaration above the useEffect that references it
- Use handleClose as proper dependency instead of eslint-disable
- Fix unused _parentId parameter type in useTreeLayout

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/components/tree-editor/NodeEditorPanel.tsx

@@ -20,7 +20,7 @@ const TYPE_CONFIG: Record<Exclude<NodeType, 'answer'>, { icon: typeof HelpCircle
 }
 
 function cloneWithoutChildren(node: TreeStructure): TreeStructure {
-  const { children, ...rest } = node
+  const { children: _children, ...rest } = node
   return structuredClone(rest) as TreeStructure
 }
 
@@ -47,17 +47,6 @@ export function NodeEditorPanel({ nodeId, onClose, onSelectType }: NodeEditorPan
     }
   }, [nodeId]) // eslint-disable-line react-hooks/exhaustive-deps
 
-  // Escape to close
-  useEffect(() => {
-    const handleKeyDown = (e: KeyboardEvent) => {
-      if (e.key === 'Escape') {
-        handleClose()
-      }
-    }
-    document.addEventListener('keydown', handleKeyDown)
-    return () => document.removeEventListener('keydown', handleKeyDown)
-  }, [isDirty]) // eslint-disable-line react-hooks/exhaustive-deps
-
   const handleDraftUpdate = useCallback((updates: Partial<TreeStructure>) => {
     setDraft(prev => prev ? { ...prev, ...updates } : prev)
     setIsDirty(true)
@@ -65,7 +54,7 @@ export function NodeEditorPanel({ nodeId, onClose, onSelectType }: NodeEditorPan
 
   const handleSave = useCallback(() => {
     if (!draft || !node) return
-    const { children, ...draftWithoutChildren } = draft
+    const { children: _children, ...draftWithoutChildren } = draft
     updateNode(nodeId, draftWithoutChildren)
 
     // Auto-create answer stubs for new decision options without next_node_id
@@ -100,6 +89,17 @@ export function NodeEditorPanel({ nodeId, onClose, onSelectType }: NodeEditorPan
     onClose()
   }, [isDirty, onClose])
 
+  // Escape to close
+  useEffect(() => {
+    const handleKeyDown = (e: KeyboardEvent) => {
+      if (e.key === 'Escape') {
+        handleClose()
+      }
+    }
+    document.addEventListener('keydown', handleKeyDown)
+    return () => document.removeEventListener('keydown', handleKeyDown)
+  }, [handleClose])
+
   const handleDelete = useCallback(() => {
     if (!treeStructure) return
     clearInboundReferences(nodeId, treeStructure, updateNode)

frontend/src/components/tree-editor/useTreeLayout.ts

@@ -60,7 +60,7 @@ export function useTreeLayout(): UseTreeLayoutResult {
 
     if (!treeStructure) return { rawNodes: nodes, rawEdges: edges }
 
-    function walk(node: TreeStructure, _parentId: string | null) {
+    function walk(node: TreeStructure, _parentId?: string | null) {
       const isCollapsed = collapsedNodeIds.has(node.id)
       const hasChildren = (node.children?.length ?? 0) > 0
       const hasErrors = validationErrors.some(e => e.nodeId === node.id && e.severity === 'error')