feat(scheduling): history view, execute/cancel lifecycle, CSV export, 7d trend

- Add 调度记录 modal: lists notifications by status, supports 标记已执行 (with
  after-mileage + notes) and 取消 for open records
- Add CSV export of filtered suggestions (UTF-8 BOM for Excel); top candidate
  per row picked by same-region > can-qualify preference
- Compute customer 7-day average alongside 30-day baseline in a single query;
  show trend indicator (up/down/flat) next to 客户日均 in list and detail card

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/server/routes/scheduling/algorithm.ts

@@ -62,6 +62,7 @@ export function toVehicleInfo(v: EnrichedVehicle): SchedulingVehicleInfo {
     department: v.department,
     manager: v.manager,
     customerAvgDaily: v.customerAvgDaily,
+    customerAvgDaily7d: v.customerAvgDaily7d,
     predictedYearEnd: v.predictedYearEnd,
     daysLeft: v.daysLeft,
   };