refactor: 重构前端代码并增加注释

frontend/src/hooks/useGraphLayout.ts

@@ -0,0 +1,21 @@
+import { useState, useCallback } from 'react';
+import type { GraphLayoutConfig } from '../types/graph';
+import { DEFAULT_LAYOUT } from '../config/layout';
+
+/**
+ * 知识图谱布局管理 Hook
+ * 负责布局状态的管理和切换
+ */
+export const useGraphLayout = () => {
+  const [layout, setLayout] = useState<GraphLayoutConfig>(DEFAULT_LAYOUT);
+
+  // 切换布局类型（目前只支持 force 力导向布局）
+  const handleLayoutChange = useCallback((newLayoutType: GraphLayoutConfig['type']) => {
+    setLayout({ type: newLayoutType });
+  }, []);
+
+  return {
+    layout,
+    handleLayoutChange,
+  };
+};