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/delayed-stream/lib/delayed_stream.js

@@ -0,0 +1,107 @@
+var Stream = require('stream').Stream;
+var util = require('util');
+
+module.exports = DelayedStream;
+function DelayedStream() {
+  this.source = null;
+  this.dataSize = 0;
+  this.maxDataSize = 1024 * 1024;
+  this.pauseStream = true;
+
+  this._maxDataSizeExceeded = false;
+  this._released = false;
+  this._bufferedEvents = [];
+}
+util.inherits(DelayedStream, Stream);
+
+DelayedStream.create = function(source, options) {
+  var delayedStream = new this();
+
+  options = options || {};
+  for (var option in options) {
+    delayedStream[option] = options[option];
+  }
+
+  delayedStream.source = source;
+
+  var realEmit = source.emit;
+  source.emit = function() {
+    delayedStream._handleEmit(arguments);
+    return realEmit.apply(source, arguments);
+  };
+
+  source.on('error', function() {});
+  if (delayedStream.pauseStream) {
+    source.pause();
+  }
+
+  return delayedStream;
+};
+
+Object.defineProperty(DelayedStream.prototype, 'readable', {
+  configurable: true,
+  enumerable: true,
+  get: function() {
+    return this.source.readable;
+  }
+});
+
+DelayedStream.prototype.setEncoding = function() {
+  return this.source.setEncoding.apply(this.source, arguments);
+};
+
+DelayedStream.prototype.resume = function() {
+  if (!this._released) {
+    this.release();
+  }
+
+  this.source.resume();
+};
+
+DelayedStream.prototype.pause = function() {
+  this.source.pause();
+};
+
+DelayedStream.prototype.release = function() {
+  this._released = true;
+
+  this._bufferedEvents.forEach(function(args) {
+    this.emit.apply(this, args);
+  }.bind(this));
+  this._bufferedEvents = [];
+};
+
+DelayedStream.prototype.pipe = function() {
+  var r = Stream.prototype.pipe.apply(this, arguments);
+  this.resume();
+  return r;
+};
+
+DelayedStream.prototype._handleEmit = function(args) {
+  if (this._released) {
+    this.emit.apply(this, args);
+    return;
+  }
+
+  if (args[0] === 'data') {
+    this.dataSize += args[1].length;
+    this._checkIfMaxDataSizeExceeded();
+  }
+
+  this._bufferedEvents.push(args);
+};
+
+DelayedStream.prototype._checkIfMaxDataSizeExceeded = function() {
+  if (this._maxDataSizeExceeded) {
+    return;
+  }
+
+  if (this.dataSize <= this.maxDataSize) {
+    return;
+  }
+
+  this._maxDataSizeExceeded = true;
+  var message =
+    'DelayedStream#maxDataSize of ' + this.maxDataSize + ' bytes exceeded.'
+  this.emit('error', new Error(message));
+};