fix equipping bought weapon

src/ship/packet/handler/message.rs

@@ -316,7 +316,12 @@ where
     EG: EntityGateway
 {
     let client = clients.get(&id).ok_or(ShipError::ClientNotFound(id))?;
-    let equip_slot = ((pkt.sub_menu & 0x7) - 1) % 4;
+    let equip_slot = if pkt.sub_menu > 0 {
+        ((pkt.sub_menu & 0x7) - 1) % 4
+    }
+    else {
+        0
+    };
     item_manager.player_equips_item(entity_gateway, &client.character, ClientItemId(pkt.item_id), equip_slot).await?;
     Ok(Box::new(None.into_iter()))
 }