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/postcss/lib/root.js

@@ -0,0 +1,61 @@
+'use strict'
+
+let Container = require('./container')
+
+let LazyResult, Processor
+
+class Root extends Container {
+  constructor(defaults) {
+    super(defaults)
+    this.type = 'root'
+    if (!this.nodes) this.nodes = []
+  }
+
+  normalize(child, sample, type) {
+    let nodes = super.normalize(child)
+
+    if (sample) {
+      if (type === 'prepend') {
+        if (this.nodes.length > 1) {
+          sample.raws.before = this.nodes[1].raws.before
+        } else {
+          delete sample.raws.before
+        }
+      } else if (this.first !== sample) {
+        for (let node of nodes) {
+          node.raws.before = sample.raws.before
+        }
+      }
+    }
+
+    return nodes
+  }
+
+  removeChild(child, ignore) {
+    let index = this.index(child)
+
+    if (!ignore && index === 0 && this.nodes.length > 1) {
+      this.nodes[1].raws.before = this.nodes[index].raws.before
+    }
+
+    return super.removeChild(child)
+  }
+
+  toResult(opts = {}) {
+    let lazy = new LazyResult(new Processor(), this, opts)
+    return lazy.stringify()
+  }
+}
+
+Root.registerLazyResult = dependant => {
+  LazyResult = dependant
+}
+
+Root.registerProcessor = dependant => {
+  Processor = dependant
+}
+
+module.exports = Root
+Root.default = Root
+
+Container.registerRoot(Root)