feat: Add JavaScript core exercises and solutions

- Implemented exercises for array high-order methods, memory and execution, switch statements, and final review.
- Added starter and answer files for each exercise to facilitate learning.
- Created a runner HTML file to execute JavaScript code and display console outputs.
- Updated README files to include exercise objectives, tasks, and usage instructions.

03-javascript-core/16-final-review/starter.js

@@ -0,0 +1,30 @@
+const reviewer = {
+  name: "林晨",
+  stage: "final-review",
+  showTitle() {
+    // 输出总复盘标题
+  },
+};
+
+const lessons = [
+  { title: "变量", score: 80, finished: true },
+  { title: "闭包", score: 92, finished: true },
+  { title: "this", score: 87, finished: true },
+  { title: "补漏练习", score: null, finished: false },
+  { title: "综合回顾", score: 95, finished: true },
+];
+
+let mentorNote;
+const reviewComment = null;
+
+function getStageText(stage) {
+  // 用 switch 返回阶段说明
+}
+
+// 任务：
+// 1. 调用 reviewer.showTitle()
+// 2. 输出 mentorNote 和 reviewComment 的区别
+// 3. 用 for + break 提取 lessons 中 score 有效的项目
+// 4. 用高阶函数统计课程标题、完成状态和平均分
+// 5. 创建 reviewerAlias 指向 reviewer，修改 stage，观察原对象是否变化
+// 6. 输出最终结果