Make InsertObjectProcedure properties nullable, require ResultType

Updated InsertObjectProcedure to make related command properties nullable and removed default initializations. Updated handler to use null-conditional access for these properties. Changed InsertResultCommand.Type to required and updated tests accordingly. Improves null safety and clarifies required fields.

tests/ReC.Tests/Application/Results/ResultProcedureTests.cs

@@ -23,7 +23,7 @@ public class ResultProcedureTests : RecApplicationTestBase
     [Test]
     public async Task InsertResultProcedure_runs_via_mediator()
     {
-        var procedure = new InsertResultCommand { ActionId = 1, StatusId = 200, Header = "h", Body = "b" };
+        var procedure = new InsertResultCommand { ActionId = 1, StatusId = 200, Header = "h", Body = "b", Type = Domain.Constants.ResultType.Main };
 
         var (sender, scope) = CreateScopedSender();
         using var _ = scope;