refactor(main.ts): 优化窗口对象类型断言的使用

将重复的 `(window as any)` 类型断言提取为 `winAny` 变量，提高代码可读性和维护性

src/main.ts

@@ -211,7 +211,8 @@ window.onload = function () {
   })
 
   // 向父窗口暴露：显示保存状态（文本、颜色、延时可选）
-  ;(window as any).showSaveStatus = (text: string, color?: string, delay?: number) => {
+  const winAny = window as any
+  winAny.showSaveStatus = (text: string, color?: string, delay?: number) => {
     try {
       const indicator = document.getElementById('save-status-indicator') as HTMLDivElement | null
       if (!indicator) return
@@ -221,11 +222,11 @@ window.onload = function () {
       indicator.style.display = 'block'
       // 清理之前的隐藏计时器
       const key = '__save_status_timer__'
-      const prev = (window as any)[key]
+      const prev = winAny[key]
       if (prev) {
         window.clearTimeout(prev)
       }
-      ;(window as any)[key] = window.setTimeout(() => {
+      winAny[key] = window.setTimeout(() => {
         indicator.style.display = 'none'
       }, duration)
     } catch (err) {