Add audit interfaces and fields to domain entities

Introduced interfaces for audit fields (AddedWhen, ChangedWhen, ChangedWho, AddedWho) and updated domain entities to implement them. Adjusted properties for consistency and nullability. Updated MappingProfile to map audit fields between DTOs and entities. Improves auditability and standardization across the domain model.

EnvelopeGenerator.Domain/Entities/Envelope.cs

@@ -1,11 +1,12 @@
-using DigitalData.UserManager.Domain.Entities;
+using System;
+using EnvelopeGenerator.Domain.Interfaces;
+using DigitalData.UserManager.Domain.Entities;
 using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 using EnvelopeGenerator.Domain.Constants;
 using Newtonsoft.Json;
 
 #if NETFRAMEWORK
-using System;
 using System.Collections.Generic;
 using System.Linq;
 #endif
@@ -14,11 +15,11 @@ namespace EnvelopeGenerator.Domain.Entities
 #if NET
     ;
 #elif NETFRAMEWORK
-    {
+{
 #endif
 
 [Table("TBSIG_ENVELOPE", Schema = "dbo")]
-public class Envelope
+public class Envelope : IHasAddedWhen, IHasChangedWhen
 {
     public Envelope()
     {
@@ -77,7 +78,7 @@ public class Envelope
 
     [Column("TITLE", TypeName = "nvarchar(128)")]
     public string
-#if NET
+#if nullable
         ?
 #endif
         Title { get; set; }
@@ -142,15 +143,14 @@ public class Envelope
     [NotMapped]
     [Column("DOC_RESULT")]
     public byte[]
-#if NET
+#if nullable
         ?
 #endif
-        DocResult
-    { get; set; }
+        DocResult { get; set; }
 
     [ForeignKey("EnvelopeTypeId")]
     public virtual EnvelopeType
-#if NET
+#if nullable
         ?
 #endif
         Type { get; set; }
@@ -164,19 +164,19 @@ public class Envelope
 #endif
 
     public List<Document>
-#if NET
+#if nullable
         ?
 #endif
         Documents { get; set; }
 
     public List<History>
-#if NET
+#if nullable
         ?
 #endif
         Histories { get; set; }
 
     public List<EnvelopeReceiver>
-#if NET
+#if nullable
         ?
 #endif
         EnvelopeReceivers { get; set; }