Apply review suggestion and fix entity concurrency tokens.

Jellyfin.Server.Implementations/JellyfinDb.cs

@@ -81,6 +81,7 @@ namespace Jellyfin.Server.Implementations
         {
             foreach (var saveEntity in ChangeTracker.Entries()
                 .Where(e => e.State == EntityState.Modified)
+                .Select(entry => entry.Entity)
                 .OfType<ISavingChanges>())
             {
                 saveEntity.OnSavingChanges();

Jellyfin.Server/CoreAppHost.cs

@@ -84,8 +84,11 @@ namespace Jellyfin.Server
         /// <inheritdoc />
         protected override IEnumerable<Assembly> GetAssembliesWithPartsInternal()
         {
+            // Jellyfin.Server
             yield return typeof(CoreAppHost).Assembly;
-            yield return Assembly.Load("Jellyfin.Server.Implementations");
+
+            // Jellyfin.Server.Implementations
+            yield return typeof(JellyfinDb).Assembly;
         }
 
         /// <inheritdoc />