fix(order): prevent duplicate subscriptions and repair invite gifts

internal/logic/public/order/getDiscount_test.go

@@ -0,0 +1,16 @@
+package order
+
+import (
+	"testing"
+
+	"github.com/perfect-panel/server/internal/types"
+	"github.com/stretchr/testify/require"
+)
+
+func TestGetDiscount_SkipsNewUserOnlyTierForExistingUser(t *testing.T) {
+	discount := getDiscount([]types.SubscribeDiscount{
+		{Quantity: 1, Discount: 90, NewUserOnly: true},
+	}, 1, false)
+
+	require.Equal(t, float64(1), discount)
+}