Save key storage on plugin disable

Ensure that all keys in KeyStorage are saved when the plugin is disabled. This prevents potential data loss by explicitly saving storage during the onDisable lifecycle event.

src/main/java/com/alttd/playerutils/PlayerUtils.java

@@ -32,6 +32,7 @@ public final class PlayerUtils extends JavaPlugin {
 
     @Override
     public void onDisable() {
+        KeyStorage.STORAGE.save();
     }
 
     private void registerCommands() {