refactor: 精简时间戳功能为简约单页面

- 将3个时间戳组件合并为一个简约页面
- 移除路由、导航栏等不必要组件
- 预填充当前时间/时间戳
- 始终显示结果框
- 清理测试文件和依赖

entrypoints/popup/App.tsx

@@ -1,27 +1,11 @@
-// App.js
-import { HashRouter as Router, Routes, Route } from 'react-router-dom';
 import TimestampPage from './pages/TimestampPage';
-import Navbar from '../../components/Navbar';
-import RoutePersistence from '../../components/RoutePersistence';
 import './App.css';
 
-// 路由配置数据
-const navItems = [{ path: '/', label: '时间戳', element: <TimestampPage /> }];
-
 function App() {
   return (
-    <Router future={{ v7_startTransition: true, v7_relativeSplatPath: true }}>
-      <RoutePersistence />
-      <div className="app">
-        <Navbar items={navItems} />
-
-        <Routes>
-          {navItems.map((item) => (
-            <Route key={item.path} path={item.path} element={item.element} />
-          ))}
-        </Routes>
-      </div>
-    </Router>
+    <div className="app">
+      <TimestampPage />
+    </div>
   );
 }