chore(frontend): 初始化 Vue 3 项目配置

- 添加 package.json，定义项目依赖和脚本
- 添加 vite.config.ts，配置 Vite 构建工具
- 添加 tsconfig.json 和 tsconfig.node.json，配置 TypeScript
- 添加 index.html，HTML 入口模板

技术栈：Vue 3.3+ / TypeScript / Element Plus / Vite / Pinia

frontend/vite.config.ts

@@ -0,0 +1,36 @@
+import { defineConfig } from 'vite'
+import vue from '@vitejs/plugin-vue'
+import { resolve } from 'path'
+import AutoImport from 'unplugin-auto-import/vite'
+import Components from 'unplugin-vue-components/vite'
+import { ElementPlusResolver } from 'unplugin-vue-components/resolvers'
+
+export default defineConfig({
+  plugins: [
+    vue(),
+    AutoImport({
+      resolvers: [ElementPlusResolver()],
+    }),
+    Components({
+      resolvers: [ElementPlusResolver()],
+    }),
+  ],
+  resolve: {
+    alias: {
+      '@': resolve(__dirname, 'src'),
+    },
+  },
+  server: {
+    port: 3000,
+    proxy: {
+      '/api': {
+        target: 'http://localhost:8080',
+        changeOrigin: true,
+      },
+    },
+  },
+  build: {
+    outDir: 'dist',
+    sourcemap: false,
+  },
+})