fix(RouterProvider): 修复初始加载状态逻辑，确保在加载前不覆盖 chrome.storage

- 将 isLoaded 的初始状态设置为 false，避免在加载初始数据前错误地覆盖存储。
- 新增测试用例，验证在 localStorage 快照过期时，loadInitialData 完成前不应覆盖 chrome.storage 的行为。

src/providers/RouterProvider.tsx

@@ -104,12 +104,7 @@ export function RouterProvider({
     getSyncSnapshot('app/recentlyUsedTools', [], isValidPageList),
   );
 
-  const [isLoaded, setIsLoaded] = useState(() => {
-    const snapshotKey = localStorage.getItem(`snapshot/${syncKey as string}`);
-    const snapshotVisible = localStorage.getItem(`snapshot/${visiblePagesKey as string}`);
-    const snapshotOrder = localStorage.getItem(`snapshot/${pageOrderKey as string}`);
-    return !!(snapshotKey && snapshotVisible && snapshotOrder);
-  });
+  const [isLoaded, setIsLoaded] = useState(false);
 
   /**
    * 从异步存储中安全溯源初始数据