fix(iap): 修复苹果IAP重复处理交易的问题

添加对已存在订阅的检查逻辑，避免重复处理相同的苹果IAP交易
添加测试恢复接口的示例代码

internal/handler/public/iap/apple/restoreHandler.go

@@ -21,4 +21,3 @@ func RestoreAppleTransactionsHandler(svcCtx *svc.ServiceContext) func(c *gin.Con
 		result.HttpResult(c, map[string]bool{"success": err == nil}, err)
 	}
 }
-

internal/logic/public/iap/apple/attachTransactionLogic.go

@@ -81,6 +81,19 @@ func (l *AttachTransactionLogic) Attach(req *types.AttachAppleTransactionRequest
 		}
 	}
 	exp := iapapple.CalcExpire(txPayload.PurchaseDate, duration)
+
+	if existTx != nil && existTx.Id > 0 {
+		token := fmt.Sprintf("iap:%s", txPayload.OriginalTransactionId)
+		existSub, err := l.svcCtx.UserModel.FindOneSubscribeByToken(l.ctx, token)
+		if err == nil && existSub != nil && existSub.Id > 0 {
+			// Already processed, return success
+			return &types.AttachAppleTransactionResponse{
+				ExpiresAt: exp.Unix(),
+				Tier:      tier,
+			}, nil
+		}
+	}
+
 	sum := sha256.Sum256([]byte(req.SignedTransactionJWS))
 	jwsHash := hex.EncodeToString(sum[:])
 	iapTx := &iapmodel.Transaction{