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/answer.js

@@ -0,0 +1,35 @@
+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);
+  });
+}
+
+const loadButton = document.getElementById("load-user-btn");
+const statusText = document.getElementById("user-status");
+const userCard = document.getElementById("user-card");
+
+async function loadUser() {
+  statusText.textContent = "加载中...";
+  userCard.innerHTML = "";
+
+  try {
+    const user = await fakeFetchUser();
+
+    userCard.innerHTML = `
+      <p>姓名：${user.name}</p>
+      <p>身份：${user.role}</p>
+      <p>当前重点：${user.focus}</p>
+    `;
+    statusText.textContent = "加载完成";
+  } catch (error) {
+    statusText.textContent = "加载失败";
+  }
+}
+
+loadButton.addEventListener("click", loadUser);