fix(userfront): prevent public env asset request

userfront-e2e/scripts/serve-userfront-build.mjs

@@ -35,6 +35,13 @@ const contentTypes = {
 const server = createServer((req, res) => {
   const url = new URL(req.url ?? '/', 'http://localhost');
   const pathname = decodeURIComponent(url.pathname);
+  if (pathname === '/') {
+    res.statusCode = 302;
+    res.setHeader('Location', '/ko/signin');
+    res.setHeader('Cache-Control', 'no-cache, max-age=0, must-revalidate');
+    res.end();
+    return;
+  }
   const relative = pathname === '/' ? '/index.html' : pathname;
   const candidate = normalize(join(root, relative));
 
@@ -48,6 +55,13 @@ const server = createServer((req, res) => {
   let servesAppShellFallback = false;
 
   if (!existsSync(filePath) || statSync(filePath).isDirectory()) {
+    if (extname(pathname)) {
+      res.statusCode = 404;
+      res.setHeader('Cache-Control', 'no-cache, max-age=0, must-revalidate');
+      res.end('Not Found');
+      return;
+    }
+
     // Flutter web 라우팅 경로(`/ko`, `/ko/signin`)도 index.html로 fallback 처리
     filePath = join(root, 'index.html');
     servesAppShellFallback = true;