feat: 添加完整的前端管理系统 (VbenAdmin)

- 添加基于 VbenAdmin + Vue3 + Element Plus 的前端管理系统
- 包含完整的 UI 组件库和工具链
- 支持多应用架构 (web-ele, backend-mock, playground)
- 包含完整的开发规范和配置
- 修复 admin 目录的子模块问题，确保正确提交

admin/docs/src/demos/vben-vxe-table/edit-cell/index.vue

@@ -0,0 +1,55 @@
+<script lang="ts" setup>
+import type { VxeGridProps } from '#/adapter/vxe-table';
+
+import { useVbenVxeGrid } from '#/adapter/vxe-table';
+
+import { getExampleTableApi } from '../mock-api';
+
+interface RowType {
+  category: string;
+  color: string;
+  id: string;
+  price: string;
+  productName: string;
+  releaseDate: string;
+}
+
+const gridOptions: VxeGridProps<RowType> = {
+  columns: [
+    { title: '序号', type: 'seq', width: 50 },
+    { editRender: { name: 'input' }, field: 'category', title: 'Category' },
+    { editRender: { name: 'input' }, field: 'color', title: 'Color' },
+    {
+      editRender: { name: 'input' },
+      field: 'productName',
+      title: 'Product Name',
+    },
+    { field: 'price', title: 'Price' },
+    { field: 'releaseDate', formatter: 'formatDateTime', title: 'Date' },
+  ],
+  editConfig: {
+    mode: 'cell',
+    trigger: 'click',
+  },
+  pagerConfig: {},
+  proxyConfig: {
+    ajax: {
+      query: async ({ page }) => {
+        return await getExampleTableApi({
+          page: page.currentPage,
+          pageSize: page.pageSize,
+        });
+      },
+    },
+  },
+  showOverflow: true,
+};
+
+const [Grid] = useVbenVxeGrid({ gridOptions });
+</script>
+
+<template>
+  <div class="vp-raw w-full">
+    <Grid />
+  </div>
+</template>