feat: add TenantLedger model and query generation

- Introduced TenantLedger model with fields for managing tenant transactions, including ID, TenantID, UserID, OrderID, transaction Type, Amount, and balance details.
- Implemented CRUD operations for TenantLedger with methods for Create, Update, Delete, and Reload.
- Generated query methods for TenantLedger to facilitate database interactions, including filtering, pagination, and aggregation functions.
- Established relationships with Order model for foreign key references.

backend/pkg/consts/consts.go

@@ -1,6 +1,10 @@
 package consts
 
-import "quyun/v2/app/requests"
+import (
+	"time"
+
+	"quyun/v2/app/requests"
+)
 
 // Format
 //
@@ -275,6 +279,10 @@ const (
 	// DefaultContentPreviewSeconds is the default preview duration in seconds when content.preview_seconds is unset/invalid.
 	// 默认试看时长（秒）：当未配置或传入非法值时使用。
 	DefaultContentPreviewSeconds int32 = 60
+
+	// DefaultOrderRefundWindow is the default refundable time window starting from paid_at.
+	// 默认退款时间窗：paid_at + 24h；租户管理侧可以通过强制退款绕过该限制（需审计）。
+	DefaultOrderRefundWindow = 24 * time.Hour
 )
 
 // content_prices
@@ -360,3 +368,101 @@ func ContentAccessStatusItems() []requests.KV {
 	}
 	return items
 }
+
+// orders
+
+// swagger:enum OrderType
+// ENUM( content_purchase, topup )
+type OrderType string
+
+// Description returns the Chinese label for the specific enum value.
+func (t OrderType) Description() string {
+	switch t {
+	case OrderTypeContentPurchase:
+		return "购买内容"
+	case OrderTypeTopup:
+		return "充值"
+	default:
+		return "未知类型"
+	}
+}
+
+// OrderTypeItems returns the KV list for FE dropdowns.
+func OrderTypeItems() []requests.KV {
+	values := OrderTypeValues()
+	items := make([]requests.KV, 0, len(values))
+	for _, v := range values {
+		items = append(items, requests.NewKV(string(v), v.Description()))
+	}
+	return items
+}
+
+// swagger:enum OrderStatus
+// ENUM( created, paid, refunding, refunded, canceled, failed )
+type OrderStatus string
+
+// Description returns the Chinese label for the specific enum value.
+func (t OrderStatus) Description() string {
+	switch t {
+	case OrderStatusCreated:
+		return "已创建"
+	case OrderStatusPaid:
+		return "已支付"
+	case OrderStatusRefunding:
+		return "退款中"
+	case OrderStatusRefunded:
+		return "已退款"
+	case OrderStatusCanceled:
+		return "已取消"
+	case OrderStatusFailed:
+		return "失败"
+	default:
+		return "未知状态"
+	}
+}
+
+// OrderStatusItems returns the KV list for FE dropdowns.
+func OrderStatusItems() []requests.KV {
+	values := OrderStatusValues()
+	items := make([]requests.KV, 0, len(values))
+	for _, v := range values {
+		items = append(items, requests.NewKV(string(v), v.Description()))
+	}
+	return items
+}
+
+// tenant_ledgers
+
+// swagger:enum TenantLedgerType
+// ENUM( credit_topup, debit_purchase, credit_refund, freeze, unfreeze, adjustment )
+type TenantLedgerType string
+
+// Description returns the Chinese label for the specific enum value.
+func (t TenantLedgerType) Description() string {
+	switch t {
+	case TenantLedgerTypeCreditTopup:
+		return "充值入账"
+	case TenantLedgerTypeDebitPurchase:
+		return "购买扣款"
+	case TenantLedgerTypeCreditRefund:
+		return "退款回滚"
+	case TenantLedgerTypeFreeze:
+		return "冻结"
+	case TenantLedgerTypeUnfreeze:
+		return "解冻"
+	case TenantLedgerTypeAdjustment:
+		return "人工调账"
+	default:
+		return "未知类型"
+	}
+}
+
+// TenantLedgerTypeItems returns the KV list for FE dropdowns.
+func TenantLedgerTypeItems() []requests.KV {
+	values := TenantLedgerTypeValues()
+	items := make([]requests.KV, 0, len(values))
+	for _, v := range values {
+		items = append(items, requests.NewKV(string(v), v.Description()))
+	}
+	return items
+}