fix: show Add Device button in Web environment

mixly/common/modules/mixly-modules/common/app.js

@@ -174,7 +174,8 @@ class App extends Component {
                 id: 'port-add-btn',
                 displayText: Msg.Lang['nav.btn.addDevice'],
                 preconditionFn: () => {
-                if (goog.isElectron || Env.hasSocketServer) {
+                    // 在 Web 环境下始终显示添加设备按钮
+                    if (goog.isElectron) {
                         return false;
                     }
                     return true;