feat(mileage): 外部三选筛选 + 车牌多选粘贴 + 运营区域 + xlsx 下载

- 外部行改为 批次型号 / 运营区域 / 车牌多选；按部门、按客户移入详情面板
- 车牌多选支持从 Excel 粘贴（换行/逗号/空格分隔），未匹配项显示警告
- 新增运营区域筛选：基于 136 批次区域映射（华东/华南/西南/西北）
- 新增 xlsx 数据下载，导出当前筛选结果（带表头样式与列宽）

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/server/routes/mileage/cache.ts

@@ -1,8 +1,17 @@
+import { readFileSync } from 'node:fs';
+import { fileURLToPath } from 'node:url';
+import { dirname, join } from 'node:path';
 import pool from '../../db.js';
 import mileagePool from '../../mileage-db.js';
 import { fetchVehicleInfoMap } from './vehicle-info.js';
 import type { CachedVehicle, MonitoringCache, MonitoringFilters, PlatePrefix, VehicleInfoRow } from './types.js';
 
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const regionMap: Record<string, string> = JSON.parse(
+  readFileSync(join(__dirname, 'region-map.json'), 'utf8')
+);
+const REGION_ORDER = ['华东区域', '华南区域', '西南区域', '西北区域', '华北区域', '华中区域', '东北区域'];
+
 let monitoringCache: MonitoringCache | null = null;
 
 export function getCache(): MonitoringCache | null {
@@ -38,7 +47,14 @@ function buildFilters(vehicles: CachedVehicle[], targetNames: string[]): Monitor
     .map(([prefix, count]) => ({ prefix, count }))
     .sort((a, b) => b.count - a.count);
 
-  return { departments, customers, plates, projects, entities, rentStatuses, platePrefixes, targetNames };
+  const regionSet = new Set(vehicles.map(v => v.region).filter((r): r is string => r !== null));
+  const regions = Array.from(regionSet).sort((a, b) => {
+    const ai = REGION_ORDER.indexOf(a);
+    const bi = REGION_ORDER.indexOf(b);
+    return (ai === -1 ? 99 : ai) - (bi === -1 ? 99 : bi);
+  });
+
+  return { departments, customers, plates, projects, entities, rentStatuses, platePrefixes, targetNames, regions };
 }
 
 interface MileageRow {
@@ -99,6 +115,7 @@ function mergeVehicles(
       rentStatus: info?.rent_status || null,
       entity: info?.entity || null,
       project: info?.project || null,
+      region: regionMap[m.plate] || null,
       yesterdayKm: yesterdayMap.get(m.plate) || 0,
     };
   });