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/toPlainObject.js

@@ -0,0 +1,32 @@
+var copyObject = require('./_copyObject'),
+    keysIn = require('./keysIn');
+
+/**
+ * Converts `value` to a plain object flattening inherited enumerable string
+ * keyed properties of `value` to own properties of the plain object.
+ *
+ * @static
+ * @memberOf _
+ * @since 3.0.0
+ * @category Lang
+ * @param {*} value The value to convert.
+ * @returns {Object} Returns the converted plain object.
+ * @example
+ *
+ * function Foo() {
+ *   this.b = 2;
+ * }
+ *
+ * Foo.prototype.c = 3;
+ *
+ * _.assign({ 'a': 1 }, new Foo);
+ * // => { 'a': 1, 'b': 2 }
+ *
+ * _.assign({ 'a': 1 }, _.toPlainObject(new Foo));
+ * // => { 'a': 1, 'b': 2, 'c': 3 }
+ */
+function toPlainObject(value) {
+  return copyObject(value, keysIn(value));
+}
+
+module.exports = toPlainObject;