feat: 实现供水运营专题大屏BI可视化

- 新增OperationDashboard.vue全屏大屏组件
- 添加6个核心KPI指标卡片: 进水总量/出水总量/产销差率/营收额/平均水质/报警次数
- 实现6个ECharts图表: 供水趋势/水质分布/报警统计/管网空间/设备状态/营收分析
- 创建静态HTML版本operation-dashboard.html，使用CDN加载Vue3/ECharts/Element Plus
- 更新路由配置，添加/operation路径支持
- 修复nextTick导入问题，优化build脚本

🚧 开发者: bot_dev1
📝 任务: #38 [BI] 运营仪表盘 + 供水专题大屏

frontend/node_modules/dayjs/esm/locale/en.js

@@ -0,0 +1,12 @@
+// English [en]
+// We don't need weekdaysShort, weekdaysMin, monthsShort in en.js locale
+export default {
+  name: 'en',
+  weekdays: 'Sunday_Monday_Tuesday_Wednesday_Thursday_Friday_Saturday'.split('_'),
+  months: 'January_February_March_April_May_June_July_August_September_October_November_December'.split('_'),
+  ordinal: function ordinal(n) {
+    var s = ['th', 'st', 'nd', 'rd'];
+    var v = n % 100;
+    return "[" + n + (s[(v - 20) % 10] || s[v] || s[0]) + "]";
+  }
+};