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/result.js

@@ -0,0 +1,42 @@
+'use strict'
+
+let Warning = require('./warning')
+
+class Result {
+  get content() {
+    return this.css
+  }
+
+  constructor(processor, root, opts) {
+    this.processor = processor
+    this.messages = []
+    this.root = root
+    this.opts = opts
+    this.css = ''
+    this.map = undefined
+  }
+
+  toString() {
+    return this.css
+  }
+
+  warn(text, opts = {}) {
+    if (!opts.plugin) {
+      if (this.lastPlugin && this.lastPlugin.postcssPlugin) {
+        opts.plugin = this.lastPlugin.postcssPlugin
+      }
+    }
+
+    let warning = new Warning(text, opts)
+    this.messages.push(warning)
+
+    return warning
+  }
+
+  warnings() {
+    return this.messages.filter(i => i.type === 'warning')
+  }
+}
+
+module.exports = Result
+Result.default = Result