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.

05-es6-plus/08-fetch-and-json/answer.js

@@ -0,0 +1,19 @@
+const loadButton = document.getElementById("load-btn");
+const status = document.getElementById("status");
+const output = document.getElementById("output");
+
+async function loadPost() {
+  status.textContent = "加载中...";
+
+  try {
+    const res = await fetch("https://jsonplaceholder.typicode.com/posts/1");
+    const data = await res.json();
+
+    status.textContent = "加载完成";
+    output.textContent = `标题：${data.title}\n\n内容：${data.body}`;
+  } catch (error) {
+    status.textContent = "加载失败";
+  }
+}
+
+loadButton.addEventListener("click", loadPost);