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/09-async-await-panel/starter.js

@@ -0,0 +1,18 @@
+function fakeFetchUser() {
+  return new Promise(function (resolve) {
+    setTimeout(function () {
+      resolve({
+        name: "林晨",
+        role: "前端学习者",
+        focus: "DOM + 事件 + 异步",
+      });
+    }, 900);
+  });
+}
+
+// 任务：
+// 1. 获取按钮、状态文字、信息面板
+// 2. 写一个 async 函数
+// 3. 用 await 等待 fakeFetchUser()
+// 4. 渲染用户信息
+// 5. 用 try...catch 处理异常