fix(syb): retry drifting sync page once (#270)

server/app/goauto/sybimport/sync.go

@@ -285,6 +285,24 @@ func loadDailyList(ctx context.Context, client *sybclient.Client, date string, p
 		if pageCount != len(page) {
 			return nil, fmt.Errorf("%s 货运单列表第 %d 页响应条数不自洽：total=%d，list=%d", date, pageIndex, pageCount, len(page))
 		}
+		// SYB may change a page while the list is being read. Re-read once
+		// before treating a boundary-page count drift as a fatal snapshot error.
+		if len(page) != expectedPageCount {
+			pause := time.NewTimer(500 * time.Millisecond)
+			select {
+			case <-ctx.Done():
+				pause.Stop()
+				return nil, ctx.Err()
+			case <-pause.C:
+			}
+			page, pageCount, err = client.ListPage(ctx, date, date, start, pageIndex, pageSize)
+			if err != nil {
+				return nil, fmt.Errorf("重读 %s 货运单列表第 %d 页失败：%w", date, pageIndex, err)
+			}
+			if pageCount != len(page) {
+				return nil, fmt.Errorf("%s 货运单列表第 %d 页重读响应条数不自洽：total=%d，list=%d", date, pageIndex, pageCount, len(page))
+			}
+		}
 		// Validate the whole page first: a same-page duplicate must not be
 		// hidden behind an earlier, recoverable cross-page overlap.
 		pageSeen := make(map[int64]int, len(page))