Доработано сохранение состояния

BotPages.Core/Storage/InMemoryStateStorage.cs

@@ -19,6 +19,10 @@ public sealed class InMemoryStateStorage : IStateStorage
     /// <inheritdoc />
     public Task SetAsync<T>(CompositeSessionKey session, string key, T state, CancellationToken ct)
     {
+        if (!_store.ContainsKey(session))
+        {
+            _store[session] = new();
+        }
         _store[session][key] = state!;
         return Task.CompletedTask;
     }