Player-to-Player Trade Mod

Initial release

First public release of the trading mod.

• Added server-side only player trading system (clients not required)
• Trade request flow with clickable [Start Trade] / [Deny] buttons
• 54-slot (6×9) trade GUI with separate offer areas and fixed UI slots
• 5s start countdown and 3s commit countdown
• Trade cancels safely on GUI close; items are returned
• Quick Move (Shift-click) blocked to prevent bypass/duplication issues
• Pre-commit inventory space check (main inventory + hotbar) to avoid forced drops/scams
• /trade language <en|kor|jp> for per-player message language