Fix Strategy.CopyTo: Load() was overwriting Security/Portfolio

Security and Portfolio were set before Load(Save()), so
deserialization wiped them with empty values. Moved assignments
after Load. Added Clone_PreservesSecurityAndPortfolio test.

Author: mikasoukhov

Algo.Strategies/Strategy.cs

@@ -2862,15 +2862,16 @@ protected virtual void CopyTo(Strategy copy)
 		if (copy is null)
 			throw new ArgumentNullException(nameof(copy));
 
+		var id = copy.Id;
+		copy.Load(this.Save());
+		copy.Id = id;
+
+		// set after Load to avoid being overwritten by deserialization
 		//copy.Connector = Connector;
 		copy.Security = Security;
 		copy.Portfolio = Portfolio;
 		copy.PortfolioProvider = PortfolioProvider;
 
-		var id = copy.Id;
-		copy.Load(this.Save());
-		copy.Id = id;
-
 		copy.Environment.AddRange(Environment);
 	}
 

Tests/StrategyParamTests.cs

@@ -1,5 +1,7 @@
 namespace StockSharp.Tests;
 
+using StockSharp.Designer;
+
 [TestClass]
 public class StrategyParamTests : BaseTestClass
 {
@@ -799,6 +801,30 @@ public void Step_Decimal_CommaCulture()
 		}
 	}
 
+	[TestMethod]
+	public void Clone_PreservesSecurityAndPortfolio()
+	{
+		var security = new Security { Id = "AAPL@NASDAQ", PriceStep = 0.01m };
+		var portfolio = Portfolio.CreateSimulator();
+
+		var original = new SmaStrategy
+		{
+			Security = security,
+			Portfolio = portfolio,
+			Volume = 1,
+			CandleType = TimeSpan.FromMinutes(5).TimeFrame(),
+			Long = 80,
+			Short = 30,
+		};
+
+		var clone = (SmaStrategy)original.Clone();
+
+		AreEqual(security.Id, clone.Security?.Id, "Security must survive Clone");
+		AreEqual(portfolio.Name, clone.Portfolio?.Name, "Portfolio must survive Clone");
+		AreEqual(80, clone.Long, "Long param must survive Clone");
+		AreEqual(30, clone.Short, "Short param must survive Clone");
+	}
+
 	private class TestStrategy : Strategy
 	{
 		// Simple test strategy for testing parameter functionality