升级Vue3，iView替换ElementPlus

- 删除babel配置、更新依赖与入口初始化
- 全量替换UI组件、样式适配，新增迁移文档与标签/过滤器自动化替换脚本

buyer/src/assets/styles/element.scss

@@ -0,0 +1,35 @@
+:root {
+  --el-color-primary: #ff5c58;
+  --el-color-success: #68cabe;
+  --el-color-warning: #fa6419;
+  --el-color-danger: #ff3c2a;
+  --el-font-size-base: 14px;
+}
+
+.el-button--primary {
+  --el-button-bg-color: #ff5c58;
+  --el-button-border-color: #ff5c58;
+  --el-button-hover-bg-color: #ff7875;
+  --el-button-hover-border-color: #ff7875;
+}
+
+.el-table--border {
+  .el-table__cell {
+    border-right: none !important;
+  }
+}
+
+.link-text {
+  color: #409eff;
+  cursor: pointer;
+  text-decoration: none;
+
+  &:hover {
+    color: #66b1ff;
+  }
+}
+
+.op-split {
+  margin: 0 8px;
+  color: #dcdfe6;
+}