[Added] Fully customizable shop system via a new shop.yml file. You can now configure item materials, slots, prices, amounts, and display names.
[Added] Inventory saving mechanism that automatically stores and restores player items, armor, and levels after leaving the arena or disconnecting.
[Added] Interactive join signs! Admins can easily create clickable join signs by looking at a sign and using /gd sign <arena>.
[Added] Configurable minimum and maximum player limits for arenas, manageable via /gd setminplayers and /gd setmaxplayers.
[Changed] Reorganized the ShopManager logic to dynamically read from the configuration instead of using hardcoded items.
[Changed] Updated English, Czech, and German language files with new command usage and error messages.

[Fix] Prevented inventory wipes by replacing the legacy clear method with the new inventory restore system during the game end.