Move InsertObjectResult mapping to Fluent API

Removed [Column] attribute from InsertObjectResult and configured column mapping for NewObjectId in RecDbContext using the Fluent API. This centralizes entity mapping logic in the DbContext.

src/ReC.Domain/QueryOutput/InsertObjectResult.cs

@@ -4,6 +4,5 @@ namespace ReC.Domain.QueryOutput;
 
 public class InsertObjectResult
 {
-    [Column("oGUID")]
     public required long NewObjectId { get; set; }
 }