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/flatMapDepth.js

@@ -0,0 +1,31 @@
+import baseFlatten from './_baseFlatten.js';
+import map from './map.js';
+import toInteger from './toInteger.js';
+
+/**
+ * This method is like `_.flatMap` except that it recursively flattens the
+ * mapped results up to `depth` times.
+ *
+ * @static
+ * @memberOf _
+ * @since 4.7.0
+ * @category Collection
+ * @param {Array|Object} collection The collection to iterate over.
+ * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+ * @param {number} [depth=1] The maximum recursion depth.
+ * @returns {Array} Returns the new flattened array.
+ * @example
+ *
+ * function duplicate(n) {
+ *   return [[[n, n]]];
+ * }
+ *
+ * _.flatMapDepth([1, 2], duplicate, 2);
+ * // => [[1, 1], [2, 2]]
+ */
+function flatMapDepth(collection, iteratee, depth) {
+  depth = depth === undefined ? 1 : toInteger(depth);
+  return baseFlatten(map(collection, iteratee), depth);
+}
+
+export default flatMapDepth;