feat: Update join/leave messages for Velocity network

LoHub:
- Changed join message to 'connected to hub' (Russian)
- Changed quit message to 'left' (Russian)
- Messages show only on actual join/leave, not server switches

LoVelocity:
- Added ServerSwitchListener
- Velocity handles server switches silently
- Backend servers (LoHub) show join/leave messages

Result: Clean join/leave messages across the network

lohub/src/main/resources/config.yml

@@ -160,8 +160,11 @@ anti_swear:
 
 join_leave_messages:
   enabled: true
-  join_message: "&#6BCB77+ &#FFD700%player% &#AAAAAAconnected"
+  # Сообщение при подключении к хабу
-  quit_message: "&#FF6B6B- &#FFD700%player% &#AAAAAAdisconnected"
+  # Пустая строка '' = не показывать сообщение
+  join_message: "&#6BCB77+ &#FFD700%player% &#AAAAAAподключился к хабу"
+  # Сообщение при выходе с сервера (не при переключении на другой сервер)
+  quit_message: "&#FF6B6B- &#FFD700%player% &#AAAAAAвышел"
 
 join_events:
   - "[MESSAGE] &#FFD700╔═══════════════════════════════╗"

lovelocity/src/main/java/com/loki/lovelocity/LoVelocity.java

@@ -38,6 +38,7 @@ public class LoVelocity {
         logger.info("Version: 1.5.5");
 
         registerCommands();
+        registerListeners();
     }
 
     private void registerCommands() {
@@ -51,6 +52,11 @@ public class LoVelocity {
         logger.info("Commands registered: /hub, /lobby");
     }
 
+    private void registerListeners() {
+        server.getEventManager().register(this, new com.loki.lovelocity.listeners.ServerSwitchListener(this));
+        logger.info("Listeners registered");
+    }
+
     public ProxyServer getServer() {
         return server;
     }

lovelocity/src/main/java/com/loki/lovelocity/listeners/ServerSwitchListener.java

@@ -0,0 +1,28 @@
+package com.loki.lovelocity.listeners;
+
+import com.loki.lovelocity.LoVelocity;
+import com.velocitypowered.api.event.PostOrder;
+import com.velocitypowered.api.event.Subscribe;
+import com.velocitypowered.api.event.connection.DisconnectEvent;
+import com.velocitypowered.api.event.player.ServerConnectedEvent;
+
+public class ServerSwitchListener {
+
+    private final LoVelocity plugin;
+
+    public ServerSwitchListener(LoVelocity plugin) {
+        this.plugin = plugin;
+    }
+
+    @Subscribe(order = PostOrder.LAST)
+    public void onServerConnected(ServerConnectedEvent event) {
+        // Velocity doesn't show join/leave messages by default
+        // They are handled by backend servers (Paper/Spigot)
+    }
+
+    @Subscribe(order = PostOrder.LAST)
+    public void onDisconnect(DisconnectEvent event) {
+        // Velocity doesn't show join/leave messages by default
+        // They are handled by backend servers (Paper/Spigot)
+    }
+}