feat: add operator and business reference fields to tenant ledgers

- Added `operator_user_id`, `biz_ref_type`, and `biz_ref_id` fields to the TenantLedger model for enhanced auditing and traceability.
- Updated the tenant ledgers query generation to include new fields.
- Introduced new API endpoint for retrieving tenant ledger records with filtering options based on the new fields.
- Enhanced Swagger documentation to reflect the new endpoint and its parameters.
- Created DTOs for admin ledger filtering and item representation.
- Implemented the admin ledger retrieval logic in the tenant service.
- Added database migration scripts to introduce new fields and indexes for efficient querying.

backend/database/models/tenant_ledgers.gen.go

@@ -31,6 +31,9 @@ type TenantLedger struct {
 	Remark         string                  `gorm:"column:remark;type:character varying(255);not null;comment:备注：业务说明/后台操作原因等；用于审计" json:"remark"`                                                                    // 备注：业务说明/后台操作原因等；用于审计
 	CreatedAt      time.Time               `gorm:"column:created_at;type:timestamp with time zone;not null;default:now();comment:创建时间：默认 now()" json:"created_at"`                                                   // 创建时间：默认 now()
 	UpdatedAt      time.Time               `gorm:"column:updated_at;type:timestamp with time zone;not null;default:now();comment:更新时间：默认 now()" json:"updated_at"`                                                   // 更新时间：默认 now()
+	OperatorUserID int64                   `gorm:"column:operator_user_id;type:bigint;comment:操作者用户ID：谁触发该流水（admin/buyer/system）；用于审计与追责；可为空（历史数据或无法识别时）" json:"operator_user_id"`                                   // 操作者用户ID：谁触发该流水（admin/buyer/system）；用于审计与追责；可为空（历史数据或无法识别时）
+	BizRefType     string                  `gorm:"column:biz_ref_type;type:character varying(32);comment:业务引用类型：order/refund/topup/etc；与 biz_ref_id 组成可选的结构化幂等/追溯键" json:"biz_ref_type"`                             // 业务引用类型：order/refund/topup/etc；与 biz_ref_id 组成可选的结构化幂等/追溯键
+	BizRefID       int64                   `gorm:"column:biz_ref_id;type:bigint;comment:业务引用ID：与 biz_ref_type 配合使用（例如 orders.id）；用于对账与审计" json:"biz_ref_id"`                                                         // 业务引用ID：与 biz_ref_type 配合使用（例如 orders.id）；用于对账与审计
 	Order          *Order                  `gorm:"foreignKey:OrderID;references:ID" json:"order,omitempty"`
 }