fix: use viewport-based height for node editor panel

Replace h-full with calc(100vh - 105px) to bypass the CSS height chain
that fails to constrain the panel across browsers. The 105px accounts
for the topbar (56px) and editor toolbar (49px).

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

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

@@ -162,7 +162,7 @@ export function NodeEditorPanel({ nodeId, onClose, onSelectType }: NodeEditorPan
   const isRoot = treeStructure?.id === nodeId
 
   return (
-    <div ref={panelRef} className="flex h-full min-h-0 w-[400px] shrink-0 flex-col border-l border-border bg-card overflow-hidden">
+    <div ref={panelRef} className="flex h-[calc(100vh-105px)] w-[400px] shrink-0 flex-col border-l border-border bg-card">
       {/* Header */}
       <div className="flex items-center gap-2 border-b border-border px-4 py-3 shrink-0">
         <span className={cn('flex h-5 w-5 shrink-0 items-center justify-center rounded', config.badgeClass)}>