feat: add ChangeEntry model for version/change tracking

Models/ServiceTicket.cs

@@ -3,10 +3,6 @@ using System.Collections.Generic;
 
 namespace Disco.Plugins.ServiceTracker.Models
 {
-    /// <summary>
-    /// Extended ticket metadata stored alongside Disco Job records.
-    /// Links to a Disco Job by JobId.
-    /// </summary>
     public class ServiceTicket
     {
         public int JobId { get; set; }
@@ -18,6 +14,7 @@ namespace Disco.Plugins.ServiceTracker.Models
         public string StatusOverride { get; set; }
         public string Summary { get; set; }
         public List<TicketNote> Notes { get; set; }
+        public List<ChangeEntry> ChangeLog { get; set; }
         public DateTime CreatedDate { get; set; }
         public DateTime LastModifiedDate { get; set; }
         public string LastModifiedBy { get; set; }
@@ -25,6 +22,7 @@ namespace Disco.Plugins.ServiceTracker.Models
         public ServiceTicket()
         {
             Notes = new List<TicketNote>();
+            ChangeLog = new List<ChangeEntry>();
             CreatedDate = DateTime.Now;
             LastModifiedDate = DateTime.Now;
         }
@@ -37,7 +35,7 @@ namespace Disco.Plugins.ServiceTracker.Models
         public string AuthorName { get; set; }
         public DateTime Timestamp { get; set; }
         public string Content { get; set; }
-        public string NoteType { get; set; } // "update", "escalation", "resolution", "general"
+        public string NoteType { get; set; }
 
         public TicketNote()
         {
@@ -46,4 +44,18 @@ namespace Disco.Plugins.ServiceTracker.Models
             NoteType = "general";
         }
     }
+
+    public class ChangeEntry
+    {
+        public DateTime Timestamp { get; set; }
+        public string UserId { get; set; }
+        public string Field { get; set; }
+        public string OldValue { get; set; }
+        public string NewValue { get; set; }
+
+        public ChangeEntry()
+        {
+            Timestamp = DateTime.Now;
+        }
+    }
 }