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/09-final-modern-js/answer.js

@@ -0,0 +1,22 @@
+import { baseSummary, loadExtraSkills } from "./summary-service.js";
+
+const title = document.getElementById("title");
+const intro = document.getElementById("intro");
+const skillList = document.getElementById("skill-list");
+
+async function renderPage() {
+  const extraSkills = await loadExtraSkills();
+  const { name, stage, skills } = baseSummary;
+  const allSkills = [...skills, ...extraSkills];
+
+  title.textContent = `${name} 的 ${stage} 学习摘要`;
+  intro.textContent = `当前已覆盖 ${allSkills.length} 个现代 JS 关键点。`;
+
+  allSkills.forEach((skill) => {
+    const item = document.createElement("li");
+    item.textContent = `已掌握：${skill}`;
+    skillList.appendChild(item);
+  });
+}
+
+renderPage();