chore: 初始化前端项目脚手架与构建配置

Vue 3 + TypeScript + Vite 工程配置，包含 package.json、tsconfig、vite.config.ts 及 .gitignore（忽略 node_modules/dist/自动生成类型声明）。

frontend/tsconfig.app.json

@@ -0,0 +1,25 @@
+{
+  "compilerOptions": {
+    "target": "ES2020",
+    "useDefineForClassFields": true,
+    "module": "ESNext",
+    "lib": ["ES2020", "DOM", "DOM.Iterable"],
+    "skipLibCheck": true,
+    "moduleResolution": "bundler",
+    "allowImportingTsExtensions": true,
+    "isolatedModules": true,
+    "moduleDetection": "force",
+    "noEmit": true,
+    "jsx": "preserve",
+    "strict": true,
+    "noUnusedLocals": false,
+    "noUnusedParameters": false,
+    "noFallthroughCasesInSwitch": true,
+    "baseUrl": ".",
+    "paths": {
+      "@/*": ["src/*"]
+    },
+    "types": ["element-plus/global"]
+  },
+  "include": ["src/**/*.ts", "src/**/*.tsx", "src/**/*.vue", "auto-imports.d.ts", "components.d.ts"]
+}