Phase 1 #20 #23: 通用模块 + Vue3 前端框架搭建

#20 通用模块:
- MinioService: MinIO 文件上传/下载/桶管理
- @DataScope 注解: 数据权限切片
- ExcelUtils: EasyExcel 导出
- IdUtils: Snowflake ID 生成器
- BaseEntity: MyBatis-Plus 基础实体

#23 前端框架:
- Vue3 + TypeScript + Vite + Element Plus + ECharts + Pinia
- 路由系统: 登录守卫 + 动态路由
- 登录页: 渐变背景 + Axios+Sa-Token 认证
- 仪表盘: 统计卡片 + 供水趋势折线图 + 片区饼图
- MainLayout: 侧边栏菜单 + 顶栏用户下拉(退出)
- API 层: Axios 请求/响应拦截器 + Token 自动注入
- 系统管理骨架: 用户/角色/菜单/部门 列表页

frontend/src/components/layout/MainLayout.vue

@@ -0,0 +1,53 @@
+<template>
+  <el-container style="height:100vh">
+    <el-aside width="220px" class="sidebar">
+      <div class="logo">💧 智慧水务</div>
+      <el-menu :default-active="route.path" router background-color="#304156" text-color="#bfcbd9" active-text-color="#409EFF">
+        <el-menu-item index="/dashboard"><el-icon><DataAnalysis /></el-icon>供水总览</el-menu-item>
+        <el-sub-menu index="system">
+          <template #title><el-icon><Setting /></el-icon>系统管理</template>
+          <el-menu-item index="/system/user">用户管理</el-menu-item>
+          <el-menu-item index="/system/role">角色管理</el-menu-item>
+          <el-menu-item index="/system/menu">菜单管理</el-menu-item>
+          <el-menu-item index="/system/dept">部门管理</el-menu-item>
+        </el-sub-menu>
+      </el-menu>
+    </el-aside>
+    <el-container>
+      <el-header class="topbar">
+        <span class="title">精河县供水工程综合管理平台</span>
+        <el-dropdown @command="handleCommand">
+          <span class="user">{{ userStore.realName || '管理员' }} <el-icon><ArrowDown /></el-icon></span>
+          <template #dropdown>
+            <el-dropdown-menu>
+              <el-dropdown-item>个人中心</el-dropdown-item>
+              <el-dropdown-item command="logout">退出登录</el-dropdown-item>
+            </el-dropdown-menu>
+          </template>
+        </el-dropdown>
+      </el-header>
+      <el-main><router-view /></el-main>
+    </el-container>
+  </el-container>
+</template>
+
+<script setup lang="ts">
+import { useRoute, useRouter } from 'vue-router'
+import { useUserStore } from '@/store/user'
+
+const route = useRoute()
+const router = useRouter()
+const userStore = useUserStore()
+
+function handleCommand(cmd: string) {
+  if (cmd === 'logout') { userStore.logout(); router.push('/login') }
+}
+</script>
+
+<style scoped>
+.sidebar { background:#304156; overflow-y:auto }
+.logo { color:#fff; text-align:center; padding:16px; font-size:18px; font-weight:bold; border-bottom:1px solid rgba(255,255,255,.1) }
+.topbar { background:#fff; display:flex; align-items:center; justify-content:space-between; border-bottom:1px solid #e6e6e6 }
+.title { font-size:16px; color:#333 }
+.user { cursor:pointer; color:#666 }
+</style>