feat(stages): 添加性能测试和虚拟DOM实现阶段

添加stage04-perf用于真实DOM操作性能对比，包含三个不同的更新策略：
- innerHTML全量更新
- createElement全量重建
- 精确单节点更新

添加stage04用于模拟异步接口数据获取后的渲染演示

添加stage05实现虚拟DOM基础功能，提供VNode对象描述DOM树结构和递
归渲染函数

stage04/index.js

@@ -0,0 +1,103 @@
+/**
+ * Stage 04：模拟异步接口
+ * 演示数据从接口获取后再渲染
+ */
+
+/**
+ * 根据用户数据生成卡片 DOM 节点
+ * @param {{ name: string, age: number, tag: string }} user
+ * @returns {HTMLDivElement}
+ */
+function generateUser(user) {
+  const card = document.createElement("div");
+  card.className = "user-card";
+
+  const name = document.createElement("h2");
+  name.textContent = "姓名: " + user.name;
+
+  const age = document.createElement("p");
+  age.textContent = "年龄: " + user.age;
+
+  const tag = document.createElement("span");
+  tag.textContent = user.tag;
+
+  card.appendChild(name);
+  card.appendChild(age);
+  card.appendChild(tag);
+  return card;
+}
+
+/**
+ * 将用户卡片挂载到指定容器
+ * @param {{ name: string, age: number, tag: string }} user
+ * @param {HTMLElement} container
+ */
+function renderUser(user, container) {
+  container.appendChild(generateUser(user));
+}
+
+/**
+ * 渲染用户列表（先清空容器）
+ * @param {{ name: string, age: number, tag: string }[]} users
+ * @param {HTMLElement} container
+ */
+function renderUserList(users, container) {
+  container.innerHTML = ""; // 清空原有内容
+  for (let i = 0; i < users.length; i++) {
+    renderUser(users[i], container);
+  }
+}
+
+// 模拟数据库
+const multiUser = [
+  { name: "小明", age: 18, tag: "学生" },
+  { name: "小王", age: 19, tag: "学生" },
+  { name: "小李", age: 20, tag: "学生" },
+  { name: "小孙", age: 56, tag: "校长" },
+  { name: "小赵", age: 43, tag: "老师" },
+];
+
+/**
+ * 模拟异步获取用户数据
+ * @param {number} id
+ * @returns {Promise<{ name: string, age: number, tag: string }[]>}
+ */
+async function getUser(id) {
+  await new Promise((resolve) => setTimeout(resolve, 500));
+  const count = Math.min(Math.max(1, id), multiUser.length);
+  return multiUser.slice(0, count);
+}
+
+const root = document.getElementById("minivue");
+const loadBtn = /** @type {HTMLButtonElement} */ (
+  document.getElementById("loadBtn")
+);
+const userIdInput = /** @type {HTMLInputElement} */ (
+  document.getElementById("userId")
+);
+
+userIdInput.value = "1";
+
+loadBtn.addEventListener("click", async () => {
+  const rawValue = userIdInput.value.trim();
+  const id = parseInt(rawValue, 10);
+
+  if (isNaN(id) || id < 1) {
+    alert("请输入一个大于 0 的数字 ID");
+    return;
+  }
+
+  loadBtn.disabled = true;
+  loadBtn.textContent = "加载中...";
+
+  try {
+    const users = await getUser(id);
+    renderUserList(users, root);
+  } catch (err) {
+    console.error("加载失败", err);
+    alert("加载失败，请重试");
+  } finally {
+    loadBtn.disabled = false;
+    loadBtn.textContent = "加载用户";
+  }
+});