feat: Add Vue3 exercises and interview plan

- Introduced Vue3 exercises covering composable API, reactivity, lifecycle hooks, and built-in components.
- Added structured interview plan for frontend candidates focusing on HTML, CSS, JavaScript, TypeScript, and Vue.
- Included starter files for each exercise and detailed README documentation for guidance.

08-vue3/03-watch-and-watch-effect/starter.js

@@ -0,0 +1,30 @@
+const { createApp, ref, computed, watch, watchEffect } = Vue;
+
+createApp({
+  setup() {
+    const keyword = ref("");
+    const courses = ref([
+      { id: 1, title: "ref 和 reactive" },
+      { id: 2, title: "watch 和 watchEffect" },
+      { id: 3, title: "组件通信" },
+    ]);
+
+    const filteredCourses = computed(() => {
+      // 任务：根据 keyword 过滤课程
+      return courses.value;
+    });
+
+    watch(keyword, (newValue, oldValue) => {
+      // 任务：输出关键字变化日志
+    });
+
+    watchEffect(() => {
+      // 任务：输出当前筛选后的数量
+    });
+
+    return {
+      keyword,
+      filteredCourses,
+    };
+  },
+}).mount("#app");