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/03-arrow-functions/answer.js

@@ -0,0 +1,15 @@
+const getLevel = (score) => (score >= 80 ? "达标" : "继续练习");
+const add = (a, b) => a + b;
+
+const tracks = ["DOM", "异步", "模块化"];
+const labels = tracks.map((track) => `[${track}]`);
+
+document.getElementById("output").textContent = JSON.stringify(
+  {
+    level: getLevel(86),
+    sum: add(12, 8),
+    labels,
+  },
+  null,
+  2
+);