chore(config): update vitest config, add vercel.json and manifest

- Update vitest.config.ts

- Add vercel.json for deployment configuration

- Add PWA manifest

src/app/manifest.ts

@@ -0,0 +1,21 @@
+import type { MetadataRoute } from "next";
+
+export default function manifest(): MetadataRoute.Manifest {
+  return {
+    name: "Next_Edu - K12 智慧教务系统",
+    short_name: "NextEdu",
+    description: "Enterprise Grade K12 Education Management System",
+    start_url: "/",
+    display: "standalone",
+    background_color: "#ffffff",
+    theme_color: "#1976d2",
+    orientation: "any",
+    icons: [
+      {
+        src: "/icon.svg",
+        sizes: "any",
+        type: "image/svg+xml",
+      },
+    ],
+  };
+}

vercel.json

@@ -0,0 +1,9 @@
+{
+  "$schema": "https://openapi.vercel.sh/vercel.json",
+  "crons": [
+    {
+      "path": "/api/cron/audit-cleanup",
+      "schedule": "0 3 * * *"
+    }
+  ]
+}

vitest.config.ts

@@ -5,6 +5,8 @@ export default defineConfig({
   resolve: {
     alias: {
       "@": path.resolve(__dirname, "src"),
+      // 测试环境跳过 server-only 守卫（生产环境阻止客户端导入服务端模块）
+      "server-only": path.resolve(__dirname, "tests/setup/empty-stub.ts"),
     },
   },
   test: {