Fix people sort order (#14852)

Jellyfin.Server.Implementations/Item/PeopleRepository.cs

@@ -98,13 +98,18 @@ public class PeopleRepository(IDbContextFactory<JellyfinDbContext> dbProvider, I
         var personsEntities = toAdd.Concat(existingPersons).ToArray();
 
         var existingMaps = context.PeopleBaseItemMap.Include(e => e.People).Where(e => e.ItemId == itemId).ToList();
+
+        var maxSortOrder = Math.Max(
+            context.PeopleBaseItemMap.Include(e => e.People).Where(e => e.ItemId == itemId && e.People.PersonType == PersonKind.Actor.ToString()).Max(e => (int?)e.SortOrder) ?? 0,
+            people.Where(p => p.Type == PersonKind.Actor && p.SortOrder.HasValue).Max(p => (int?)p.SortOrder) ?? 0);
+
         foreach (var person in people)
         {
             var entityPerson = personsEntities.First(e => e.Name == person.Name && e.PersonType == person.Type.ToString());
             var existingMap = existingMaps.FirstOrDefault(e => e.People.Name == person.Name && e.Role == person.Role);
             if (existingMap is null)
             {
-                var sortOrder = (person.SortOrder ?? context.PeopleBaseItemMap.Where(e => e.ItemId == itemId).Max(e => e.SortOrder) ?? 0) + 1;
+                var sortOrder = person.Type == PersonKind.Actor ? (person.SortOrder ?? ++maxSortOrder) : person.SortOrder;
                 context.PeopleBaseItemMap.Add(new PeopleBaseItemMap()
                 {
                     Item = null!,