fix unstable sorting of items with the same scheduled date.

ports/mysql/items.go

@@ -166,7 +166,7 @@ func (r *itemRepository) Fetch(ctx context.Context, filter models.ItemFilter) ([
 	}
 
 	sort.Slice(res, func(i, j int) bool {
-		// Most recently acquired first
+		// Acquired time, descending
 		ati, atj := res[i].AcquiredTime, res[j].AcquiredTime
 		if ati == nil && atj != nil {
 			return true
@@ -178,7 +178,7 @@ func (r *itemRepository) Fetch(ctx context.Context, filter models.ItemFilter) ([
 			return ati.After(*atj)
 		}
 
-		// Most recently scheduled next
+		// Scheduled date, ascending
 		sdi, sdj := res[i].ScheduledDate, res[j].ScheduledDate
 		if sdi != nil && sdj == nil {
 			return true
@@ -186,11 +186,11 @@ func (r *itemRepository) Fetch(ctx context.Context, filter models.ItemFilter) ([
 		if sdi == nil && sdj != nil {
 			return false
 		}
-		if sdi != nil && sdj != nil {
+		if sdi != nil && sdj != nil && *sdi != *sdj {
 			return sdi.Before(*sdj)
 		}
 
-		// Created last
+		// Created time, descending
 		return res[i].CreatedTime.After(res[j].CreatedTime)
 	})