feat: 新增自定义图标库并调整菜单图标与菜单归属

1. 新增 iconfont 自定义图标库及相关依赖文件
2. 调整菜单图标为自定义字体图标，替换原有 Ant Design 图标
3. 将客户拜访菜单从客户管理移动到项目管理作为首个子菜单
4. 优化侧边菜单展开逻辑与图标样式适配

client/src/main.ts

@@ -2,6 +2,7 @@ import { createApp } from "vue";
 import Antd from "ant-design-vue";
 import "ant-design-vue/dist/reset.css";
 import "@/assets/styles/global.less";
+import "@/assets/fonts/iconfont/iconfont.css";
 import App from "./App.vue";
 import router from "./router";
 import pinia from "./stores";