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/05-form-submit-and-prevent-default/starter.js

@@ -0,0 +1,6 @@
+// 任务：
+// 1. 获取表单、输入框和列表
+// 2. 监听 submit 事件
+// 3. 用 preventDefault() 阻止默认提交
+// 4. 读取输入框内容，创建新 li，追加到列表
+// 5. 清空输入框