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/lodash-es/flatMap.js

@@ -0,0 +1,29 @@
+import baseFlatten from './_baseFlatten.js';
+import map from './map.js';
+
+/**
+ * Creates a flattened array of values by running each element in `collection`
+ * thru `iteratee` and flattening the mapped results. The iteratee is invoked
+ * with three arguments: (value, index|key, collection).
+ *
+ * @static
+ * @memberOf _
+ * @since 4.0.0
+ * @category Collection
+ * @param {Array|Object} collection The collection to iterate over.
+ * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+ * @returns {Array} Returns the new flattened array.
+ * @example
+ *
+ * function duplicate(n) {
+ *   return [n, n];
+ * }
+ *
+ * _.flatMap([1, 2], duplicate);
+ * // => [1, 1, 2, 2]
+ */
+function flatMap(collection, iteratee) {
+  return baseFlatten(map(collection, iteratee), 1);
+}
+
+export default flatMap;