fix integration

backend/src/api/services/transactions.go

@@ -31,12 +31,13 @@ func NewTransactionService(repo repositories.TransactionRepository, activityRepo
 }
 
 var (
-	ErrTransactionNotFound = errors.New("transaction not found")
-	ErrTransactionPatch    = errors.New("empty update payload")
-	ErrReceiptLinkConflict = errors.New("receipt_id and detach_receipt cannot be used together")
-	ErrInvalidTransaction  = errors.New("type and category are required")
-	ErrReceiptNotFound     = errors.New("receipt not found")
-	ErrInvalidAnalytics    = errors.New("type must be income or expense")
+	ErrTransactionNotFound  = errors.New("transaction not found")
+	ErrTransactionPatch     = errors.New("empty update payload")
+	ErrReceiptLinkConflict  = errors.New("receipt_id and detach_receipt cannot be used together")
+	ErrReceiptAlreadyExists = errors.New("receipt already exists")
+	ErrInvalidTransaction   = errors.New("type and category are required")
+	ErrReceiptNotFound      = errors.New("receipt not found")
+	ErrInvalidAnalytics     = errors.New("type must be income or expense")
 )
 
 func (s *transactionService) Create(ctx context.Context, req domain.CreateTransactionRequest) (*domain.Transaction, error) {