优化号主交接超时卡死问题

- 号主交接超时(owner_timeout)后允许补提交交接说明，避免临时延误导致订单卡死
- 后台新增"重置交接"动作，可将超时订单恢复为待号主交接并刷新计时
- 交接超时改以进入待交接时刻为基准计算，新增 handoff_started_at 字段

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/src/features/orders/api/orders.ts

@@ -321,6 +321,13 @@ export async function adminMarkOrderAbnormal(id: number, reason: string) {
   return data.data
 }
 
+export async function adminResetHandoff(id: number, reason: string) {
+  const { data } = await apiClient.post<ApiResponse<Order>>(`/admin/orders/${id}/reset-handoff`, {
+    reason,
+  })
+  return data.data
+}
+
 export async function adminRefundStatus(id: number) {
   const { data } = await apiClient.get<ApiResponse<RefundStatus>>(
     `/admin/orders/${id}/refund-status`