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-vue2/03-v-model-and-form/starter.js

@@ -0,0 +1,10 @@
+new Vue({
+  el: "#app",
+  data: {
+    nickname: "",
+    goal: "",
+    stage: "入门",
+    pace: "每天学习",
+    skills: [],
+  },
+});