refactor(system): revise calcNextPosition

examples/react/src/examples/Subflow/index.tsx

@@ -13,6 +13,7 @@ import {
   MiniMap,
   Background,
   Panel,
+  NodeOrigin,
 } from '@xyflow/react';
 
 import DebugNode from './DebugNode';
@@ -119,6 +120,7 @@ const initialNodes: Node[] = [
     data: { label: 'Node 3' },
     position: { x: 400, y: 100 },
     className: 'light',
+    extent: 'parent',
   },
 ];