feat: add feedback comments activity notifications

backend/src/Socialize.Api/Modules/Feedback/Handlers/CancelMyFeedback.cs

@@ -54,11 +54,25 @@ public class CancelMyFeedbackHandler(AppDbContext dbContext)
         }
 
         DateTimeOffset now = DateTimeOffset.UtcNow;
+        FeedbackStatus previousStatus = report.Status;
         report.Status = FeedbackStatus.Cancelled;
         report.CancelledAt = now;
         report.CancelledByUserId = reporterUserId;
         report.CancellationReason = string.IsNullOrWhiteSpace(request.Reason) ? null : request.Reason.Trim();
         report.LastActivityAt = now;
+        report.ActivityEntries.Add(new FeedbackActivityEntry
+        {
+            Id = Guid.NewGuid(),
+            FeedbackReportId = report.Id,
+            ActorUserId = reporterUserId,
+            ActorDisplayName = User.GetAlias() ?? User.GetName(),
+            ActorEmail = User.GetEmail(),
+            ActivityType = FeedbackActivityTypes.Cancelled,
+            FromValue = previousStatus.ToFeedbackDisplayString(),
+            ToValue = FeedbackStatus.Cancelled.ToFeedbackDisplayString(),
+            Note = report.CancellationReason,
+            CreatedAt = now,
+        });
 
         await dbContext.SaveChangesAsync(ct);
         await SendOkAsync(report.ToDto(), ct);