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/join.js

@@ -0,0 +1,26 @@
+/** Used for built-in method references. */
+var arrayProto = Array.prototype;
+
+/* Built-in method references for those with the same name as other `lodash` methods. */
+var nativeJoin = arrayProto.join;
+
+/**
+ * Converts all elements in `array` into a string separated by `separator`.
+ *
+ * @static
+ * @memberOf _
+ * @since 4.0.0
+ * @category Array
+ * @param {Array} array The array to convert.
+ * @param {string} [separator=','] The element separator.
+ * @returns {string} Returns the joined string.
+ * @example
+ *
+ * _.join(['a', 'b', 'c'], '~');
+ * // => 'a~b~c'
+ */
+function join(array, separator) {
+  return array == null ? '' : nativeJoin.call(array, separator);
+}
+
+module.exports = join;