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/@cesium/engine/Source/Scene/findContentMetadata.js

@@ -0,0 +1,51 @@
+import ContentMetadata from "./ContentMetadata.js";
+import Frozen from "../Core/Frozen.js";
+import defined from "../Core/defined.js";
+import hasExtension from "./hasExtension.js";
+import oneTimeWarning from "../Core/oneTimeWarning.js";
+
+/**
+ * Check if a content has metadata, either defined in its metadata field (3D Tiles 1.1) or in
+ * the <code>3DTILES_metadata</code> extension. If defined, get the content metadata
+ * with the corresponding class.
+ *
+ * @function
+ *
+ * @param {Cesium3DTileset} tileset The tileset to query for content metadata
+ * @param {object} contentHeader the JSON header for a {@link Cesium3DTileContent}
+ * @return {ContentMetadata} the content metadata, or <code>undefined</code> if not found
+ * @private
+ * @experimental This feature is using part of the 3D Tiles spec that is not final and is subject to change without Cesium's standard deprecation policy.
+ */
+function findContentMetadata(tileset, contentHeader) {
+  const metadataJson = hasExtension(contentHeader, "3DTILES_metadata")
+    ? contentHeader.extensions["3DTILES_metadata"]
+    : contentHeader.metadata;
+
+  if (!defined(metadataJson)) {
+    return undefined;
+  }
+
+  if (!defined(tileset.schema)) {
+    findContentMetadata._oneTimeWarning(
+      "findContentMetadata-missing-root-schema",
+      "Could not find a metadata schema for content metadata. For tilesets that contain external tilesets, make sure the schema is added to the root tileset.json.",
+    );
+    return undefined;
+  }
+
+  const classes = tileset.schema.classes ?? Frozen.EMPTY_OBJECT;
+  if (defined(metadataJson.class)) {
+    const contentClass = classes[metadataJson.class];
+    return new ContentMetadata({
+      content: metadataJson,
+      class: contentClass,
+    });
+  }
+
+  return undefined;
+}
+
+// Exposed for testing
+findContentMetadata._oneTimeWarning = oneTimeWarning;
+export default findContentMetadata;