feat: add TypeScript lessons and learning panel

- Introduced a new script to check TypeScript lesson files for errors.
- Created a main TypeScript file to render lessons and their details.
- Added lesson definitions with starter and answer codes.
- Implemented a user interface for navigating and running lessons.
- Styled the application with CSS for a better user experience.
- Updated README to reflect the new TypeScript section and usage instructions.

04-dom-events-async/07-timers-and-async-order/starter.js

@@ -0,0 +1,6 @@
+// 任务：
+// 1. 获取按钮和日志列表
+// 2. 点击按钮后清空旧日志
+// 3. 先追加“开始执行”
+// 4. 用 setTimeout 延迟追加“异步回调完成”
+// 5. 再立刻追加“同步代码结束”