feat: 去除basic auth认证，添加登录和登出 API，更新中间件以支持 cookie 验证

app/api/auth/logout/route.ts

@@ -0,0 +1,7 @@
+import { NextResponse } from 'next/server';
+
+export async function POST() {
+  const response = NextResponse.json({ success: true });
+  response.cookies.delete('auth_token');
+  return response;
+}