优化安全性

public/js/app.js

@@ -192,6 +192,7 @@
   function updateUserUI(username) {
     if (username) {
       user = username;
+      dom.btnSettings.style.display = 'flex';
       dom.userSection.innerHTML = `
         <div class="user-info">
           <span class="username">${escapeHtml(username)}</span>
@@ -201,6 +202,7 @@
       document.getElementById('btnLogout').addEventListener('click', handleLogout);
     } else {
       user = null;
+      dom.btnSettings.style.display = 'none';
       dom.userSection.innerHTML = `<button class="btn btn-login" id="btnLogin">登录</button>`;
       document.getElementById('btnLogin').addEventListener('click', openLoginModal);
     }