feat(退款): AUG26-006 退款方式选择与原路退款

按 PRD 2.3/2.4/2.5 落地套餐退款的方式矩阵与原路渠道退款：

- 退款申请派生并冻结权威实收金额（线上取原成功支付记录，钱包/线下取订单实际收款），
  提交人不可填写或修改；按来源支付方式生成可选方式矩阵并在创建、提交、执行前重复校验。
- 审批切换为「每次提交一条不可变审批尝试记录 + 独立企业微信审批实例」，业务标识取尝试
  记录主键；终态消费按尝试记录优先、退款申请兜底双读，兼容存量无实例与已关联实例申请。
  新增活动退款部分唯一索引 (order_id) WHERE status IN (1,5,6)。
- 本地人工终审保持既有开关，补齐通过入口的 approval_instance_id IS NULL 守卫，使三个
  入口一致拒绝已关联审批实例的申请；重提按尝试模式重写（仅已拒绝/已退回/原路失败且无异常）。
- 权益时点：企微通过事务写退款终态、按方式确定的订单态、钱包回款、员工账单冲销与可靠
  失效事实；套餐失效/接续/停机仍由既有可靠机制最终一致执行，不把外部调用放入资金事务。
  订单支付状态按方式置位：凭证退款与退回原钱包在企微通过时置已退款，原路须渠道明确成功。
- 按官方契约实现微信直连 v3、微信 v2（双向证书）、富友（/commonRefund 与 /refundQuery）、
  支付宝四类原路退款；能力只由服务商类型与退款必需凭证完整性决定，无人工开关。
  渠道请求号在提交时冻结到尝试记录，并以 channel_submitted_at 条件认领保证资金动作至多
  提交一次（重复投递只查询不二次提交）；不向任何渠道传递退款结果通知地址。
- 新增 refund:channel:recovery 恢复任务只查询回填；本地查询窗口超期（富友 72 小时、
  微信 v2 7 天）转原路退款失败、渠道状态已失败、分类超时未知并置异常转人工，不放行自动
  重提以避免重复退款。
- 同步退款 DTO/导出/审计资源与审计查询关联、商户凭证文档，并修正 fuiou 集成契约文档。

迁移 000218（退款尝试与渠道退款事实）、000219（微信 v2 客户端证书凭证）成对提供，
未修改既有迁移；测试库 junhong_cmp_test 完成 up/down/up 与行为核对，未调用真实渠道。

internal/application/refundapproval/creation.go

@@ -4,9 +4,12 @@ package refundapproval
 import (
 	"context"
 	"fmt"
+	"strconv"
 	"strings"
+	"time"
 
 	"github.com/bytedance/sonic"
+	"gorm.io/datatypes"
 	"gorm.io/gorm"
 	"gorm.io/gorm/clause"
 
@@ -21,6 +24,8 @@ type CreateCommand struct {
 	Refund             *model.RefundRequest
 	Order              *model.Order
 	SubmitterAccountID uint
+	// Attempt 是本次提交或重提新增的不可变审批尝试记录，其主键同时作为通用审批业务标识。
+	Attempt *model.RefundRequestAttempt
 }
 
 // ApplicationAudit 描述退款申请、审批、订单和提交人的同事务审计事实。
@@ -29,6 +34,12 @@ type ApplicationAudit struct {
 	Order     *model.Order
 	Approval  *model.ApprovalInstance
 	Submitter *model.Account
+	// Attempt 非空时表示本次写入新增了一条审批尝试记录。
+	Attempt *model.RefundRequestAttempt
+	// Action 与 EventID 为空时按「首次提交」写入；重提时由调用方显式指定，
+	// 使同一次重提的审计事件在该尝试上保持幂等。
+	Action  string
+	EventID string
 }
 
 // AuditWriter 接收退款申请事务内审计事实。
@@ -39,11 +50,16 @@ type AuditWriter interface {
 // CreateResult 返回原子保存后的退款申请和初始审批状态。
 type CreateResult struct {
 	Refund         *model.RefundRequest
+	Attempt        *model.RefundRequestAttempt
 	SubmitterName  string
 	ApprovalStatus int
 }
 
-// CreationService 原子创建退款申请、通用审批实例、企微上下文和提交 Outbox。
+// CreationService 原子创建退款申请、审批尝试记录、通用审批实例和提交 Outbox。
+//
+// 每次提交或重提新增一条不可变审批尝试记录，并以尝试记录主键作为通用审批业务标识，
+// 使同一退款单的每次提交各自持有独立审批实例；退款单只保存最新尝试与最新实例引用用于展示，
+// 其既有 approval_instance_id 语义与唯一约束保持不变。
 type CreationService struct {
 	db       *gorm.DB
 	approval approvalapp.Port
@@ -55,8 +71,8 @@ func NewCreationService(db *gorm.DB, approval approvalapp.Port, audit AuditWrite
 	return &CreationService{db: db, approval: approval, audit: audit}
 }
 
-// Execute 在业务写入前校验审批渠道，并在同一事务冻结退款事实和审批事实。
 // TriggerHistorical 为历史待审批退款补发一次企业微信审批。
+// 历史申请尚未接入尝试模式，因此本次补发同时建立首条尝试记录并把业务标识切换到该记录。
 func (s *CreationService) TriggerHistorical(ctx context.Context, refundID uint) (*CreateResult, error) {
 	if s == nil || s.db == nil || s.approval == nil || s.audit == nil || refundID == 0 {
 		return nil, errors.New(errors.CodeServiceUnavailable, "退款审批能力未配置")
@@ -91,12 +107,8 @@ func (s *CreationService) TriggerHistorical(ctx context.Context, refundID uint)
 	if err != nil {
 		return nil, err
 	}
-	submitterSnapshot, requestSnapshot, err := refundSnapshots(&refund, account)
-	if err != nil {
-		return nil, err
-	}
 
-	var approvalStatus int
+	var result *CreateResult
 	err = s.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
 		var current model.RefundRequest
 		if err := tx.WithContext(ctx).Clauses(clause.Locking{Strength: "UPDATE"}).First(&current, refundID).Error; err != nil {
@@ -113,47 +125,61 @@ func (s *CreationService) TriggerHistorical(ctx context.Context, refundID uint)
 		if err := tx.WithContext(ctx).First(&currentOrder, current.OrderID).Error; err != nil {
 			return errors.Wrap(errors.CodeDatabaseError, err, "查询退款关联订单失败")
 		}
+
+		attempt, err := buildAttempt(ctx, tx, &current, &currentOrder)
+		if err != nil {
+			return err
+		}
+		attempt.SubmittedByAccountID = current.Creator
+
+		submitterSnapshot, requestSnapshot, err := refundSnapshots(&current, account)
+		if err != nil {
+			return err
+		}
 		reference, err := s.approval.CreateInTx(ctx, tx, approvalapp.CreateRequest{
 			Preparation: preparation, BusinessType: constants.ApprovalBusinessTypeRefund,
-			BusinessID: current.ID, SubmitterAccountID: current.Creator,
+			BusinessID: attempt.ID, SubmitterAccountID: current.Creator,
 			SubmitterSnapshot: submitterSnapshot, RequestSnapshot: requestSnapshot,
 			CorrelationID: current.RefundNo,
 		})
 		if err != nil {
 			return err
 		}
-		result := tx.WithContext(ctx).Model(&model.RefundRequest{}).
-			Where("id = ? AND status = ? AND approval_instance_id IS NULL", current.ID, model.RefundStatusPending).
-			Update("approval_instance_id", reference.InstanceID)
-		if result.Error != nil {
-			return errors.Wrap(errors.CodeDatabaseError, result.Error, "关联退款审批实例失败")
+		if err := attachAttemptInstance(ctx, tx, attempt, reference.InstanceID); err != nil {
+			return err
 		}
-		if result.RowsAffected != 1 {
-			return errors.New(errors.CodeConflict, "退款审批实例关联已变化")
+		if err := updateRefundLatest(ctx, tx, &current, attempt, reference.InstanceID); err != nil {
+			return err
 		}
+
 		current.ApprovalInstanceID = &reference.InstanceID
 		refund = current
 		order = currentOrder
-		approvalStatus = reference.Status
 		var instance model.ApprovalInstance
 		if err := tx.WithContext(ctx).First(&instance, reference.InstanceID).Error; err != nil {
 			return errors.Wrap(errors.CodeDatabaseError, err, "查询退款审批审计快照失败")
 		}
-		return s.audit.WriteRefundApplication(ctx, tx, ApplicationAudit{
-			Refund: &current, Order: &currentOrder, Approval: &instance, Submitter: account,
-		})
+		if err := s.audit.WriteRefundApplication(ctx, tx, ApplicationAudit{
+			Refund: &current, Order: &currentOrder, Approval: &instance, Submitter: account, Attempt: attempt,
+		}); err != nil {
+			return err
+		}
+		result = &CreateResult{Refund: &refund, Attempt: attempt, SubmitterName: account.Username, ApprovalStatus: reference.Status}
+		return nil
 	})
 	if err != nil {
 		return nil, err
 	}
-	return &CreateResult{Refund: &refund, SubmitterName: account.Username, ApprovalStatus: approvalStatus}, nil
+	return result, nil
 }
 
+// Execute 在业务写入前校验审批渠道，并在同一事务冻结退款事实、审批尝试事实和审批事实。
 func (s *CreationService) Execute(ctx context.Context, command CreateCommand) (*CreateResult, error) {
 	if s == nil || s.db == nil || s.approval == nil || s.audit == nil {
 		return nil, errors.New(errors.CodeServiceUnavailable, "退款审批能力未配置")
 	}
-	if command.Refund == nil || command.Order == nil || command.Refund.OrderID == 0 || command.Order.ID != command.Refund.OrderID || command.SubmitterAccountID == 0 ||
+	if command.Refund == nil || command.Order == nil || command.Attempt == nil ||
+		command.Refund.OrderID == 0 || command.Order.ID != command.Refund.OrderID || command.SubmitterAccountID == 0 ||
 		command.Refund.Creator != command.SubmitterAccountID || strings.TrimSpace(command.Refund.RefundNo) == "" {
 		return nil, errors.New(errors.CodeInvalidParam)
 	}
@@ -179,33 +205,34 @@ func (s *CreationService) Execute(ctx context.Context, command CreateCommand) (*
 		}
 		var activeCount int64
 		if err := tx.WithContext(ctx).Model(&model.RefundRequest{}).
-			Where("order_id = ? AND status IN ?", command.Refund.OrderID, []int{model.RefundStatusPending, model.RefundStatusApproved}).
+			Where("order_id = ? AND status IN ?", command.Refund.OrderID, model.RefundActiveStatuses()).
 			Count(&activeCount).Error; err != nil {
 			return errors.Wrap(errors.CodeDatabaseError, err, "复核订单活跃退款申请失败")
 		}
 		if activeCount > 0 {
-			return errors.New(errors.CodeConflict, "该订单已存在退款申请")
+			return errors.New(errors.CodeConflict, "该订单已存在活动退款申请")
 		}
 		if err := tx.WithContext(ctx).Create(command.Refund).Error; err != nil {
 			return errors.Wrap(errors.CodeDatabaseError, err, "创建退款申请失败")
 		}
+		command.Attempt.RefundID = command.Refund.ID
+		if err := tx.WithContext(ctx).Create(command.Attempt).Error; err != nil {
+			return errors.Wrap(errors.CodeDatabaseError, err, "创建退款审批尝试记录失败")
+		}
 		reference, err := s.approval.CreateInTx(ctx, tx, approvalapp.CreateRequest{
 			Preparation: preparation, BusinessType: constants.ApprovalBusinessTypeRefund,
-			BusinessID: command.Refund.ID, SubmitterAccountID: command.SubmitterAccountID,
+			BusinessID: command.Attempt.ID, SubmitterAccountID: command.SubmitterAccountID,
 			SubmitterSnapshot: submitterSnapshot, RequestSnapshot: requestSnapshot,
 			CorrelationID: command.Refund.RefundNo,
 		})
 		if err != nil {
 			return err
 		}
-		result := tx.WithContext(ctx).Model(&model.RefundRequest{}).
-			Where("id = ? AND approval_instance_id IS NULL", command.Refund.ID).
-			Update("approval_instance_id", reference.InstanceID)
-		if result.Error != nil {
-			return errors.Wrap(errors.CodeDatabaseError, result.Error, "关联退款审批实例失败")
+		if err := attachAttemptInstance(ctx, tx, command.Attempt, reference.InstanceID); err != nil {
+			return err
 		}
-		if result.RowsAffected != 1 {
-			return errors.New(errors.CodeConflict, "退款审批实例关联已变化")
+		if err := updateRefundLatest(ctx, tx, command.Refund, command.Attempt, reference.InstanceID); err != nil {
+			return err
 		}
 		command.Refund.ApprovalInstanceID = &reference.InstanceID
 		approvalStatus = reference.Status
@@ -214,13 +241,165 @@ func (s *CreationService) Execute(ctx context.Context, command CreateCommand) (*
 			return errors.Wrap(errors.CodeDatabaseError, err, "查询退款审批审计快照失败")
 		}
 		return s.audit.WriteRefundApplication(ctx, tx, ApplicationAudit{
-			Refund: command.Refund, Order: command.Order, Approval: &approval, Submitter: account,
+			Refund: command.Refund, Order: command.Order, Approval: &approval, Submitter: account, Attempt: command.Attempt,
 		})
 	})
 	if err != nil {
 		return nil, err
 	}
-	return &CreateResult{Refund: command.Refund, SubmitterName: account.Username, ApprovalStatus: approvalStatus}, nil
+	return &CreateResult{Refund: command.Refund, Attempt: command.Attempt, SubmitterName: account.Username, ApprovalStatus: approvalStatus}, nil
+}
+
+// ResubmitCommand 描述重提时的材料变更。
+// Refund 携带本次重提后的新值（方式、金额、原因、客户收款信息、凭证与冻结实收），
+// Attempt 是本次新增的不可变审批尝试记录。
+type ResubmitCommand struct {
+	Refund  *model.RefundRequest
+	Attempt *model.RefundRequestAttempt
+}
+
+// Resubmit 修改并重提未成功退款申请，新增审批尝试记录与新的企业微信审批实例。
+//
+// 仅已拒绝、已退回或原路退款失败且无审批异常的申请可重提；已成功、待审批、原路处理中或
+// 存在审批异常的申请返回状态冲突。每次重提新增不可变尝试记录与独立审批实例，
+// 历史材料与审批结果不被覆盖，退款单只更新为最新尝试引用。
+func (s *CreationService) Resubmit(ctx context.Context, refundID uint, command ResubmitCommand) (*CreateResult, error) {
+	if s == nil || s.db == nil || s.approval == nil || s.audit == nil {
+		return nil, errors.New(errors.CodeServiceUnavailable, "退款审批能力未配置")
+	}
+	if refundID == 0 || command.Refund == nil || command.Attempt == nil || command.Refund.Creator == 0 {
+		return nil, errors.New(errors.CodeInvalidParam, "重提退款申请参数不完整")
+	}
+	account, err := s.loadSubmitter(ctx, command.Refund.Creator)
+	if err != nil {
+		return nil, err
+	}
+
+	var created *CreateResult
+	err = s.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
+		if err := tx.Exec("SELECT pg_advisory_xact_lock(?)", int64(refundID)).Error; err != nil {
+			return errors.Wrap(errors.CodeDatabaseError, err, "锁定退款申请重提边界失败")
+		}
+		var current model.RefundRequest
+		if err := tx.WithContext(ctx).Clauses(clause.Locking{Strength: "UPDATE"}).First(&current, refundID).Error; err != nil {
+			if err == gorm.ErrRecordNotFound {
+				return errors.New(errors.CodeNotFound, "退款申请不存在")
+			}
+			return errors.Wrap(errors.CodeDatabaseError, err, "锁定退款申请失败")
+		}
+		if !isResubmittable(&current) {
+			return errors.New(errors.CodeInvalidStatus, "当前状态不允许重新提交退款申请")
+		}
+		var order model.Order
+		if err := tx.WithContext(ctx).First(&order, current.OrderID).Error; err != nil {
+			return errors.Wrap(errors.CodeDatabaseError, err, "查询退款关联订单失败")
+		}
+
+		// 材料已在调用方校验，这里把新值并入当前事实后冻结快照。
+		current.Method = command.Refund.Method
+		current.RequestedRefundAmount = command.Refund.RequestedRefundAmount
+		current.FrozenActualReceivedAmount = command.Refund.FrozenActualReceivedAmount
+		current.RefundReason = command.Refund.RefundReason
+		current.RefundVoucherKey = command.Refund.RefundVoucherKey
+		current.CustomerAccountInfo = command.Refund.CustomerAccountInfo
+
+		attempt, err := buildAttempt(ctx, tx, &current, &order)
+		if err != nil {
+			return err
+		}
+		attempt.SubmittedByAccountID = current.Creator
+
+		preparation, err := s.approval.Prepare(ctx, approvalapp.PrepareRequest{
+			BusinessType: constants.ApprovalBusinessTypeRefund, SubmitterAccountID: current.Creator,
+			CorrelationID: current.RefundNo,
+		})
+		if err != nil {
+			return err
+		}
+		submitterSnapshot, requestSnapshot, err := refundSnapshots(&current, account)
+		if err != nil {
+			return err
+		}
+
+		// 同一事务内回写材料、回到待审批并创建新的审批实例。
+		updates := map[string]any{
+			"status":                        model.RefundStatusPending,
+			"method":                        current.Method,
+			"requested_refund_amount":       current.RequestedRefundAmount,
+			"frozen_actual_received_amount": current.FrozenActualReceivedAmount,
+			"refund_reason":                 current.RefundReason,
+			"refund_voucher_key":            current.RefundVoucherKey,
+			"customer_account_info":         current.CustomerAccountInfo,
+			"failure_reason":                "",
+			"failure_message":               "",
+			"channel_refund_status":         constants.RefundChannelStatusNone,
+			"reject_reason":                 "",
+			"processor_id":                  nil,
+			"processed_at":                  nil,
+			"updater":                       current.Creator,
+			"updated_at":                    time.Now().UTC(),
+		}
+		result := tx.WithContext(ctx).Model(&model.RefundRequest{}).
+			Where("id = ? AND status IN ?", refundID, model.RefundResubmittableStatuses()).
+			Updates(updates)
+		if result.Error != nil {
+			return errors.Wrap(errors.CodeDatabaseError, result.Error, "更新退款申请重提材料失败")
+		}
+		if result.RowsAffected != 1 {
+			return errors.New(errors.CodeConflict, "退款申请状态已变化")
+		}
+		current.Status = model.RefundStatusPending
+
+		if err := tx.WithContext(ctx).Create(attempt).Error; err != nil {
+			return errors.Wrap(errors.CodeDatabaseError, err, "创建退款审批尝试记录失败")
+		}
+		reference, err := s.approval.CreateInTx(ctx, tx, approvalapp.CreateRequest{
+			Preparation: preparation, BusinessType: constants.ApprovalBusinessTypeRefund,
+			BusinessID: attempt.ID, SubmitterAccountID: current.Creator,
+			SubmitterSnapshot: submitterSnapshot, RequestSnapshot: requestSnapshot,
+			CorrelationID: current.RefundNo,
+		})
+		if err != nil {
+			return err
+		}
+		if err := attachAttemptInstance(ctx, tx, attempt, reference.InstanceID); err != nil {
+			return err
+		}
+		if err := updateRefundLatest(ctx, tx, &current, attempt, reference.InstanceID); err != nil {
+			return err
+		}
+		var instance model.ApprovalInstance
+		if err := tx.WithContext(ctx).First(&instance, reference.InstanceID).Error; err != nil {
+			return errors.Wrap(errors.CodeDatabaseError, err, "查询退款审批审计快照失败")
+		}
+		if err := s.audit.WriteRefundApplication(ctx, tx, ApplicationAudit{
+			Refund: &current, Order: &order, Approval: &instance, Submitter: account, Attempt: attempt,
+			Action:  constants.AuditActionRefundResubmitted,
+			EventID: "refund:" + strconv.FormatUint(uint64(refundID), 10) + ":attempt:" + strconv.FormatUint(uint64(attempt.ID), 10),
+		}); err != nil {
+			return err
+		}
+		created = &CreateResult{Refund: &current, Attempt: attempt, SubmitterName: account.Username, ApprovalStatus: reference.Status}
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+	return created, nil
+}
+
+// isResubmittable 判断退款申请是否处于可重提状态且不存在审批异常。
+// 企业微信通过后撤销的申请标记异常并禁止自动重提，只能由人工线下处理。
+func isResubmittable(refund *model.RefundRequest) bool {
+	if refund == nil || refund.AnomalyFlag != 0 {
+		return false
+	}
+	for _, status := range model.RefundResubmittableStatuses() {
+		if refund.Status == status {
+			return true
+		}
+	}
+	return false
 }
 
 func (s *CreationService) loadSubmitter(ctx context.Context, accountID uint) (*model.Account, error) {
@@ -234,6 +413,104 @@ func (s *CreationService) loadSubmitter(ctx context.Context, accountID uint) (*m
 	return &account, nil
 }
 
+// buildAttempt 构造一条不可变审批尝试记录，冻结当次方式、金额、冻结实收、原因、客户收款信息与套餐使用快照。
+// attempt_no 在退款申请行已加锁的前提下于同一事务内递增，因此申请内唯一。
+func buildAttempt(ctx context.Context, tx *gorm.DB, refund *model.RefundRequest, order *model.Order) (*model.RefundRequestAttempt, error) {
+	attemptNo, err := nextAttemptNo(ctx, tx, refund.ID)
+	if err != nil {
+		return nil, err
+	}
+	snapshot, err := packageUsageSnapshot(ctx, tx, refund, order)
+	if err != nil {
+		return nil, err
+	}
+	return &model.RefundRequestAttempt{
+		RefundID:                   refund.ID,
+		AttemptNo:                  attemptNo,
+		Method:                     refund.Method,
+		RefundAmount:               refund.RequestedRefundAmount,
+		FrozenActualReceivedAmount: refund.FrozenActualReceivedAmount,
+		RefundReason:               refund.RefundReason,
+		CustomerAccountInfo:        refund.CustomerAccountInfo,
+		CustomerVoucherKeys:        refund.RefundVoucherKey,
+		PackageUsageSnapshot:       snapshot,
+		SubmittedByAccountID:       refund.Creator,
+	}, nil
+}
+
+// nextAttemptNo 返回该退款申请的下一条审批尝试序号；退款申请行已加锁，序号在同一事务内唯一。
+func nextAttemptNo(ctx context.Context, tx *gorm.DB, refundID uint) (int, error) {
+	var row struct {
+		MaxAttemptNo int
+	}
+	if err := tx.WithContext(ctx).Model(&model.RefundRequestAttempt{}).
+		Select("COALESCE(MAX(attempt_no), 0) AS max_attempt_no").
+		Where("refund_id = ?", refundID).Scan(&row).Error; err != nil {
+		return 0, errors.Wrap(errors.CodeDatabaseError, err, "查询退款审批尝试序号失败")
+	}
+	return row.MaxAttemptNo + 1, nil
+}
+
+// packageUsageSnapshot 冻结本次申请关联的套餐使用情况，作为企业微信审批判断材料。
+// 本期退款不按套餐已用流量计算金额，因此该快照只作审批与追溯材料，不参与金额校验。
+func packageUsageSnapshot(ctx context.Context, tx *gorm.DB, refund *model.RefundRequest, order *model.Order) (datatypes.JSON, error) {
+	snapshot := map[string]any{
+		"order_type":       order.OrderType,
+		"asset_identifier": order.AssetIdentifier,
+	}
+	if refund.PackageUsageID != nil && *refund.PackageUsageID > 0 {
+		var usage model.PackageUsage
+		if err := tx.WithContext(ctx).First(&usage, *refund.PackageUsageID).Error; err != nil {
+			if err != gorm.ErrRecordNotFound {
+				return nil, errors.Wrap(errors.CodeDatabaseError, err, "查询退款关联套餐使用记录失败")
+			}
+		} else {
+			snapshot["package_usage"] = map[string]any{
+				"id": usage.ID, "package_id": usage.PackageID, "package_name": usage.PackageName,
+				"usage_type": usage.UsageType, "status": usage.Status,
+				"data_limit_mb": usage.DataLimitMB, "data_usage_mb": usage.DataUsageMB,
+				"activated_at": usage.ActivatedAt, "expires_at": usage.ExpiresAt,
+			}
+		}
+	}
+	encoded, err := sonic.Marshal(snapshot)
+	if err != nil {
+		return nil, errors.Wrap(errors.CodeInternalError, err, "编码退款套餐使用快照失败")
+	}
+	return datatypes.JSON(encoded), nil
+}
+
+// attachAttemptInstance 把审批实例 ID 回写到本次审批尝试记录，写入一次后不可修改。
+func attachAttemptInstance(ctx context.Context, tx *gorm.DB, attempt *model.RefundRequestAttempt, instanceID uint) error {
+	result := tx.WithContext(ctx).Model(&model.RefundRequestAttempt{}).
+		Where("id = ? AND approval_instance_id IS NULL", attempt.ID).
+		Update("approval_instance_id", instanceID)
+	if result.Error != nil {
+		return errors.Wrap(errors.CodeDatabaseError, result.Error, "关联退款审批尝试实例失败")
+	}
+	if result.RowsAffected != 1 {
+		return errors.New(errors.CodeConflict, "退款审批尝试实例关联已变化")
+	}
+	attempt.ApprovalInstanceID = &instanceID
+	return nil
+}
+
+// updateRefundLatest 更新退款申请的最新审批尝试与最新审批实例引用，仅用于展示。
+// 既有 approval_instance_id 在该函数外单独回写，保持「首次接入企业微信审批的实例」语义不变。
+func updateRefundLatest(ctx context.Context, tx *gorm.DB, refund *model.RefundRequest, attempt *model.RefundRequestAttempt, instanceID uint) error {
+	updates := map[string]any{
+		"latest_attempt_id":           attempt.ID,
+		"latest_approval_instance_id": instanceID,
+		"updated_at":                  time.Now().UTC(),
+	}
+	if err := tx.WithContext(ctx).Model(&model.RefundRequest{}).Where("id = ?", refund.ID).Updates(updates).Error; err != nil {
+		return errors.Wrap(errors.CodeDatabaseError, err, "更新退款申请最新审批引用失败")
+	}
+	refund.LatestAttemptID = attempt.ID
+	refund.LatestApprovalInstanceID = instanceID
+	return nil
+}
+
 func refundSnapshots(refund *model.RefundRequest, account *model.Account) ([]byte, []byte, error) {
 	submitterSnapshot, err := sonic.Marshal(map[string]any{
 		"account_id": account.ID, "account_name": account.Username, "user_type": account.UserType,
@@ -247,7 +524,7 @@ func refundSnapshots(refund *model.RefundRequest, account *model.Account) ([]byt
 		constants.ApprovalFieldOrderNo:               refund.OrderNo,
 		constants.ApprovalFieldAssetIdentifier:       refund.AssetIdentifier,
 		constants.ApprovalFieldAssetType:             refund.OrderType,
-		constants.ApprovalFieldActualReceivedAmount:  formatCentAmount(refund.ActualReceivedAmount),
+		constants.ApprovalFieldActualReceivedAmount:  formatCentAmount(refund.FrozenActualReceivedAmount),
 		constants.ApprovalFieldRequestedRefundAmount: formatCentAmount(refund.RequestedRefundAmount),
 		constants.ApprovalFieldRefundVoucherKey:      []string(refund.RefundVoucherKey),
 		constants.ApprovalFieldRefundReason:          refund.RefundReason,

internal/application/refundapproval/resolve.go

@@ -0,0 +1,101 @@
+package refundapproval
+
+import (
+	"context"
+
+	"gorm.io/gorm"
+
+	"github.com/break/junhong_cmp_fiber/internal/model"
+	"github.com/break/junhong_cmp_fiber/pkg/errors"
+)
+
+// ResolveRefundInTx 按审批业务标识解析出退款申请与本次审批尝试记录。
+//
+// 退款审批的业务标识在审批尝试模式下取尝试记录主键；本能力上线前的存量申请取退款申请主键。
+// 尝试记录与退款申请来自两个独立序列，必然存在同值，因此不能只按 businessID 判定归属：
+// 必须同时匹配 approval_instance_id，才能唯一确定是尝试记录还是退款申请。
+//
+// 解析顺序固定为「尝试记录优先、退款申请兜底」：
+//  1. tb_refund_request_attempt 中 id = businessID 且 approval_instance_id = instanceID；
+//  2. tb_refund_request 中 id = businessID 且 approval_instance_id = instanceID；
+//  3. 两者均不匹配返回稳定冲突错误，绝不回落到任一候选业务单。
+//
+// attempt 在存量兼容路径下为 nil。
+func ResolveRefundInTx(ctx context.Context, tx *gorm.DB, businessID, instanceID uint) (*model.RefundRequest, *model.RefundRequestAttempt, error) {
+	if tx == nil || businessID == 0 || instanceID == 0 {
+		return nil, nil, errors.New(errors.CodeInvalidParam, "退款审批业务标识参数无效")
+	}
+
+	var attempt model.RefundRequestAttempt
+	err := tx.WithContext(ctx).
+		Where("id = ? AND approval_instance_id = ?", businessID, instanceID).
+		First(&attempt).Error
+	switch {
+	case err == nil:
+		var refund model.RefundRequest
+		if err := tx.WithContext(ctx).First(&refund, attempt.RefundID).Error; err != nil {
+			if err == gorm.ErrRecordNotFound {
+				return nil, nil, errors.New(errors.CodeConflict, "退款审批尝试记录所属退款申请不存在")
+			}
+			return nil, nil, errors.Wrap(errors.CodeDatabaseError, err, "查询退款审批关联退款申请失败")
+		}
+		return &refund, &attempt, nil
+	case err != gorm.ErrRecordNotFound:
+		return nil, nil, errors.Wrap(errors.CodeDatabaseError, err, "查询退款审批尝试记录失败")
+	}
+
+	var refund model.RefundRequest
+	err = tx.WithContext(ctx).
+		Where("id = ? AND approval_instance_id = ?", businessID, instanceID).
+		First(&refund).Error
+	switch {
+	case err == nil:
+		return &refund, nil, nil
+	case err == gorm.ErrRecordNotFound:
+		return nil, nil, errors.New(errors.CodeConflict, "退款申请的关联审批实例不一致")
+	default:
+		return nil, nil, errors.Wrap(errors.CodeDatabaseError, err, "查询退款审批关联退款申请失败")
+	}
+}
+
+// ResolveRefundIDInTx 只解析退款申请标识，供审计资源构造与查询关联使用。
+func ResolveRefundIDInTx(ctx context.Context, tx *gorm.DB, businessID, instanceID uint) (uint, error) {
+	refund, _, err := ResolveRefundInTx(ctx, tx, businessID, instanceID)
+	if err != nil {
+		return 0, err
+	}
+	return refund.ID, nil
+}
+
+// ResolveRefundForApprovalRequestInTx 解析「审批申请已建立但审批实例尚未回写到业务记录」时刻的业务归属。
+//
+// 通用审批创建用例在同一事务内先写审批实例并写审批申请审计，业务侧随后才把实例 ID 回写到
+// 审批尝试记录。该审计时刻尝试记录已存在但其 approval_instance_id 仍为空，因此按实例一致性
+// 校验的常规解析必然不命中。本函数只承认这一种在途形态：
+//
+//	attempt.id = businessID AND attempt.approval_instance_id IS NULL
+//
+// 其余情况一律返回不存在，由调用方按常规解析的错误失败关闭，不得放宽为任意未回写记录。
+func ResolveRefundForApprovalRequestInTx(ctx context.Context, tx *gorm.DB, businessID uint) (*model.RefundRequest, *model.RefundRequestAttempt, error) {
+	if tx == nil || businessID == 0 {
+		return nil, nil, errors.New(errors.CodeInvalidParam, "退款审批业务标识参数无效")
+	}
+	var attempt model.RefundRequestAttempt
+	err := tx.WithContext(ctx).
+		Where("id = ? AND approval_instance_id IS NULL", businessID).
+		First(&attempt).Error
+	if err != nil {
+		if err == gorm.ErrRecordNotFound {
+			return nil, nil, errors.New(errors.CodeNotFound, "退款审批尝试记录未回写审批实例")
+		}
+		return nil, nil, errors.Wrap(errors.CodeDatabaseError, err, "查询在途退款审批尝试记录失败")
+	}
+	var refund model.RefundRequest
+	if err := tx.WithContext(ctx).First(&refund, attempt.RefundID).Error; err != nil {
+		if err == gorm.ErrRecordNotFound {
+			return nil, nil, errors.New(errors.CodeConflict, "退款审批尝试记录所属退款申请不存在")
+		}
+		return nil, nil, errors.Wrap(errors.CodeDatabaseError, err, "查询退款审批关联退款申请失败")
+	}
+	return &refund, &attempt, nil
+}