fix: 兼容 Chrome 90 前端运行环境

- 为管理端与用户中心补齐旧浏览器运行时 API 和回归测试

- 增加现代 CSS 与选择器降级，保持现有界面效果

- 固定 Chrome 90 构建目标并补充兼容依赖

easyflow-ui-usercenter/app/package.json

@@ -28,6 +28,7 @@
     "@easyflow/types": "workspace:*",
     "@easyflow/utils": "workspace:*",
     "@element-plus/icons-vue": "^2.3.2",
+    "@ungap/structured-clone": "1.3.0",
     "@vueuse/core": "catalog:",
     "dayjs": "catalog:",
     "element-plus": "catalog:",
@@ -43,6 +44,7 @@
   },
   "devDependencies": {
     "@types/node-forge": "^1.3.14",
+    "@types/ungap__structured-clone": "1.2.0",
     "unplugin-element-plus": "catalog:"
   }
 }