feat: add Vue2 exercises for dynamic styles, lifecycle methods, component communication, and course management dashboard

- Implement dynamic styles and event handling in Vue2 with a card component.
- Create lifecycle methods exercise to simulate async data loading and instance destruction.
- Develop a component communication exercise with props, events, and slots.
- Build a comprehensive course management dashboard with filtering, statistics, and component interactions.

07-vue2/04-conditional-and-list-rendering/starter.js

@@ -0,0 +1,12 @@
+new Vue({
+  el: "#app",
+  data: {
+    isPaid: false,
+    showList: true,
+    courses: [
+      { id: 1, title: "Vue 实例", status: "已完成" },
+      { id: 2, title: "指令系统", status: "学习中" },
+      { id: 3, title: "组件通信", status: "未开始" },
+    ],
+  },
+});