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-vue3/01-create-app-and-ref/starter.js

@@ -0,0 +1,20 @@
+const { createApp, ref } = Vue;
+
+createApp({
+  setup() {
+    const title = ref("Vue3 基础入门");
+    const learnerCount = ref(16);
+
+    function increaseLearner() {
+      // 任务：
+      // 1. learnerCount 加 1
+      // 2. 在控制台输出最新人数
+    }
+
+    return {
+      title,
+      learnerCount,
+      increaseLearner,
+    };
+  },
+}).mount("#app");