实现结账流程：替换旧归还逻辑为完整结账-修正-争议流程

- 新增 order_checkouts 表，支持结账明细（消耗/押金扣除/退回/号主入账）
- 租客发起结账 → 号主确认 → 已完成（正常路径）
- 号主修改结账 → 租客确认修正 → 已完成（修正路径）
- 结账阶段任一方发起争议 → 后台仲裁 → 已完成/已关闭/异常（争议路径）
- 争议模块适配结账争议类型，仲裁结果新增 mark_abnormal
- 超时任务适配新的 pending_checkout_confirm 状态
- 前端结账明细面板、发起结账/确认/修正/拒绝表单全部实现
- 移除旧的 SubmitReturn/ConfirmReturn 接口

backend/internal/modules/dispute/repository.go

@@ -35,6 +35,7 @@ func (r *Repository) Create(userID uint64, orderID uint64, req CreateRequest) (*
 		if order.Status == "completed" || order.Status == "cancelled" || order.Status == "closed" {
 			return ErrInvalidDispute
 		}
+		isCheckoutDispute := order.Status == "pending_checkout_confirm" || order.Status == "pending_checkout_accept"
 		var count int64
 		if err := tx.Model(&model.Dispute{}).
 			Where("order_id = ? AND status IN ?", order.ID, []string{"open", "processing"}).
@@ -57,7 +58,7 @@ func (r *Repository) Create(userID uint64, orderID uint64, req CreateRequest) (*
 			OrderID:      order.ID,
 			InitiatorID:  userID,
 			TargetUserID: targetID,
-			Type:         req.Type,
+			Type:         disputeType(req.Type, isCheckoutDispute),
 			Status:       "open",
 			Description:  req.Description,
 			EvidenceURLS: evidence,
@@ -65,17 +66,42 @@ func (r *Repository) Create(userID uint64, orderID uint64, req CreateRequest) (*
 		if err := tx.Create(&row).Error; err != nil {
 			return err
 		}
-		order.Status = "disputing"
+		if isCheckoutDispute {
+			now := time.Now()
+			order.Status = "checkout_disputing"
+			order.HandoffStatus = "checkout_disputed"
+			order.SettlementStatus = "disputed"
+			updates := map[string]any{
+				"status":     "disputed",
+				"updated_at": now,
+			}
+			if userID == order.RenterID {
+				updates["renter_rejected_at"] = now
+			}
+			if err := tx.Model(&model.OrderCheckout{}).
+				Where("order_id = ? AND status IN ?", order.ID, []string{"submitted", "countered"}).
+				Updates(updates).Error; err != nil {
+				return err
+			}
+		} else {
+			order.Status = "disputing"
+		}
 		if err := tx.Save(&order).Error; err != nil {
 			return err
 		}
 		disputeID := row.ID
+		title := "订单进入申诉"
+		content := "对方已发起申诉，请等待客服仲裁或补充沟通记录。"
+		if isCheckoutDispute {
+			title = "订单进入结账争议"
+			content = "对方已发起结账争议，请等待客服仲裁或补充结账证据。"
+		}
 		if err := notification.Append(tx,
 			notification.Entry{
 				UserID:  targetID,
 				Type:    "dispute",
-				Title:   "订单进入申诉",
-				Content: "对方已发起申诉，请等待客服仲裁或补充沟通记录。",
+				Title:   title,
+				Content: content,
 				BizType: "dispute",
 				BizID:   &disputeID,
 			},
@@ -177,6 +203,9 @@ func (r *Repository) Arbitrate(adminID uint64, id uint64, req ArbitrateRequest,
 		if req.Result == "order_close" {
 			listing.Status = "offline"
 			account.Status = "offline"
+		} else if req.Result == "mark_abnormal" {
+			listing.Status = "abnormal"
+			account.Status = "abnormal"
 		} else {
 			listing.Status = "published"
 			account.Status = "published"
@@ -335,6 +364,8 @@ func buildArbitrationSettlement(order model.RentalOrder, req ArbitrateRequest) (
 		addRenterRefund(order.DepositAmount-deductAmount, "仲裁退回剩余押金给租客")
 	case "order_close":
 		// Only release frozen funds. No available-balance settlement happens in development mode.
+	case "mark_abnormal":
+		// 标记异常只释放冻结账务，后续由客服继续线下复核。
 	default:
 		return settlement, ErrInvalidDispute
 	}
@@ -395,11 +426,20 @@ func arbitrateOrderStatus(result string) string {
 	switch result {
 	case "full_refund", "partial_refund", "order_close":
 		return "closed"
+	case "mark_abnormal":
+		return "abnormal"
 	default:
 		return "completed"
 	}
 }
 
+func disputeType(input string, isCheckoutDispute bool) string {
+	if isCheckoutDispute {
+		return "checkout_dispute"
+	}
+	return input
+}
+
 func appendAuditLog(tx *gorm.DB, actorID uint64, action string, bizType string, bizID uint64, meta AuditMeta, detail map[string]any) error {
 	raw, err := json.Marshal(detail)
 	if err != nil {