Notify about campaign start

Hcs.WebApp/BackgroundServices/CampaignManagers/ManagerBase.cs

@@ -15,16 +15,33 @@ namespace Hcs.WebApp.BackgroundServices.CampaignManagers
         protected readonly ResultWaitState resultWaitState = resultWaitState;
         protected readonly Campaign campaign = campaign;
 
+        private IManager.ManagerState state;
         private HeadquartersService? headquartersService;
 
+        public Campaign Campaign => campaign;
+
+        public IManager.ManagerState State
+        {
+            get => state;
+            set
+            {
+                if (state != value)
+                {
+                    state = value;
+
+                    if (state == IManager.ManagerState.Started)
+                    {
+                        OnCampaignStarted?.Invoke(campaign);
+                    }
+                }
+            }
+        }
+
         protected HeadquartersService HeadquartersService => headquartersService ??= scope.ServiceProvider.GetRequiredService<HeadquartersService>();
 
         protected abstract int StepCount { get; }
 
-        public Campaign Campaign => campaign;
+        public event Action<Campaign> OnCampaignStarted;
-
-        public IManager.ManagerState State { get; protected set; } = IManager.ManagerState.Created;
-
         public event Action<Campaign>? OnCampaignProgressStep;
 
         public abstract Task ProcessAsync();