refactor: add conditional compilation for .NET and .NET Framework

EnvelopeGenerator.Domain/Entities/Config.cs

@@ -2,7 +2,12 @@
 using System.ComponentModel.DataAnnotations.Schema;
 
 namespace EnvelopeGenerator.Domain.Entities
+#if NET
+    ;
+#elif NETFRAMEWORK
     {
+#endif
+
 [Table("TBSIG_CONFIG", Schema = "dbo")]
 public class Config
 {
@@ -20,4 +25,7 @@ namespace EnvelopeGenerator.Domain.Entities
     [Column("EXPORT_PATH", TypeName = "nvarchar(256)")]
     public string ExportPath { get; set; }
 }
+
+#if NETFRAMEWORK
     }
+#endif