fix(v2): 退款自愈扫描加回溯窗(防 LIMIT 尾部饥饿)+ 清死行

RefundApplyTask 的候选查询按 out_trade_no ASC/id ASC 取前 200,succeeded 退款历史
只增不减、partially_refunded 长期驻留,超过 limit 后最新的崩溃窗口永远排在候选外
扫不到。两路查询都加 since 回溯窗:RefundStore.ListDistinctOutTradeNosByStatusSince
(completed_at>=since)、OrderStore.ListOrdersByStatusSince(updated_at>=since),旧的
无窗方法原样保留。RefundApplyTask 新增 lookback/now 参数,config.ReconcileConfig 新增
RefundApplyLookbackMin(默认 48h)。顺带按 T6 复审补 OrderTTLMin 字段注释(须 ≫ crypto
orderTTL 15min),清 sync_test.go 死行 `_ = time.Second`。

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013nMthbVEmQquxBRKb9Fj8u

main.go

@@ -77,7 +77,7 @@ func main() {
 		runner.Add("paid-spotcheck", time.Duration(rc.SpotCheckEverySec)*time.Second,
 			reconcile.PaidSpotCheckTask(orderStore, pReg, time.Duration(rc.SpotCheckWindowMin)*time.Minute, time.Now))
 		runner.Add("refund-apply-sweep", time.Duration(rc.RefundApplyEverySec)*time.Second,
-			reconcile.RefundApplyTask(orderStore, refundStore, 200))
+			reconcile.RefundApplyTask(orderStore, refundStore, time.Duration(rc.RefundApplyLookbackMin)*time.Minute, time.Now, 200))
 		runner.Add("refund-stuck-alert", time.Duration(rc.RefundApplyEverySec)*time.Second,
 			reconcile.RefundStuckAlertTask(refundStore, time.Duration(rc.RefundStuckWarnMin)*time.Minute, time.Now))
 		orphanStore := store.NewOrphanStore(db)