Fix hot reload: prevent duplicate event handlers and timer leaks

Unsubscribe all event handlers and stop/dispose timers at the start of
Startup() before re-creating objects. On first load the -= calls are
no-ops; on hot reload they remove stale handlers that would otherwise
compound with each reload. Also adds LoginComplete unsubscription to
Shutdown() for completeness.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

MosswartMassacre/PluginCore.cs

@@ -163,6 +163,42 @@ namespace MosswartMassacre
                 var isCharacterLoaded = CoreManager.Current.CharacterFilter.LoginStatus == 3;
                 var needsHotReload = IsHotReload || isCharacterLoaded;
 
+                // Clean up old event subscriptions to prevent duplicates on hot reload.
+                // C# -= with a non-subscribed handler is a no-op, so safe on first load.
+                if (_chatEventRouter != null)
+                    CoreManager.Current.ChatBoxMessage -= new EventHandler<ChatTextInterceptEventArgs>(_chatEventRouter.OnChatText);
+                CoreManager.Current.ChatBoxMessage -= new EventHandler<ChatTextInterceptEventArgs>(ChatEventRouter.AllChatText);
+                CoreManager.Current.CommandLineText -= OnChatCommand;
+                CoreManager.Current.CharacterFilter.LoginComplete -= CharacterFilter_LoginComplete;
+                CoreManager.Current.CharacterFilter.Death -= OnCharacterDeath;
+                CoreManager.Current.WorldFilter.CreateObject -= OnSpawn;
+                CoreManager.Current.WorldFilter.CreateObject -= OnPortalDetected;
+                CoreManager.Current.WorldFilter.ReleaseObject -= OnDespawn;
+                if (_inventoryMonitor != null)
+                {
+                    CoreManager.Current.WorldFilter.CreateObject -= _inventoryMonitor.OnInventoryCreate;
+                    CoreManager.Current.WorldFilter.ReleaseObject -= _inventoryMonitor.OnInventoryRelease;
+                    CoreManager.Current.WorldFilter.ChangeObject -= _inventoryMonitor.OnInventoryChange;
+                }
+                if (_gameEventRouter != null)
+                    CoreManager.Current.EchoFilter.ServerDispatch -= _gameEventRouter.OnServerDispatch;
+                WebSocket.OnServerCommand -= HandleServerCommand;
+
+                // Stop old timers before recreating (prevents timer leaks on hot reload)
+                _killTracker?.Stop();
+                if (vitalsTimer != null)
+                {
+                    vitalsTimer.Stop();
+                    vitalsTimer.Dispose();
+                    vitalsTimer = null;
+                }
+                if (commandTimer != null)
+                {
+                    commandTimer.Stop();
+                    commandTimer.Dispose();
+                    commandTimer = null;
+                }
+
                 // Initialize kill tracker (owns the 1-sec stats timer)
                 _killTracker = new KillTracker(
                     this,
@@ -280,6 +316,7 @@ namespace MosswartMassacre
                 CoreManager.Current.ChatBoxMessage -= new EventHandler<ChatTextInterceptEventArgs>(_chatEventRouter.OnChatText);
                 CoreManager.Current.CommandLineText -= OnChatCommand;
                 CoreManager.Current.ChatBoxMessage -= new EventHandler<ChatTextInterceptEventArgs>(ChatEventRouter.AllChatText);
+                CoreManager.Current.CharacterFilter.LoginComplete -= CharacterFilter_LoginComplete;
                 CoreManager.Current.CharacterFilter.Death -= OnCharacterDeath;
                 CoreManager.Current.WorldFilter.CreateObject -= OnSpawn;
                 CoreManager.Current.WorldFilter.CreateObject -= OnPortalDetected;