fix: use CMSG_OPEN_ITEM for locked containers (lockboxes)

Right-clicking a locked container (e.g. Dead-Tooth's Strong Box) was
sending CMSG_USE_ITEM with spellId=0, which the server rejects. Locked
containers (itemClass==1, inventoryType==0) now send CMSG_OPEN_ITEM
instead, letting the server auto-check the keyring for the required key.

include/game/game_handler.hpp

@@ -2007,6 +2007,9 @@ public:
     void autoEquipItemInBag(int bagIndex, int slotIndex);
     void useItemBySlot(int backpackIndex);
     void useItemInBag(int bagIndex, int slotIndex);
+    // CMSG_OPEN_ITEM — for locked containers (lockboxes); server checks keyring automatically
+    void openItemBySlot(int backpackIndex);
+    void openItemInBag(int bagIndex, int slotIndex);
     void destroyItem(uint8_t bag, uint8_t slot, uint8_t count = 1);
     void swapContainerItems(uint8_t srcBag, uint8_t srcSlot, uint8_t dstBag, uint8_t dstSlot);
     void swapBagSlots(int srcBagIndex, int dstBagIndex);

include/game/world_packets.hpp

@@ -2027,6 +2027,12 @@ public:
     static network::Packet build(uint8_t bagIndex, uint8_t slotIndex, uint64_t itemGuid, uint32_t spellId = 0);
 };
 
+/** CMSG_OPEN_ITEM packet builder (for locked containers / lockboxes) */
+class OpenItemPacket {
+public:
+    static network::Packet build(uint8_t bagIndex, uint8_t slotIndex);
+};
+
 /** CMSG_AUTOEQUIP_ITEM packet builder */
 class AutoEquipItemPacket {
 public:

src/game/game_handler.cpp

@@ -21165,6 +21165,26 @@ void GameHandler::useItemInBag(int bagIndex, int slotIndex) {
     }
 }
 
+void GameHandler::openItemBySlot(int backpackIndex) {
+    if (backpackIndex < 0 || backpackIndex >= inventory.getBackpackSize()) return;
+    if (inventory.getBackpackSlot(backpackIndex).empty()) return;
+    if (state != WorldState::IN_WORLD || !socket) return;
+    auto packet = OpenItemPacket::build(0xFF, static_cast<uint8_t>(23 + backpackIndex));
+    LOG_INFO("openItemBySlot: CMSG_OPEN_ITEM bag=0xFF slot=", (23 + backpackIndex));
+    socket->send(packet);
+}
+
+void GameHandler::openItemInBag(int bagIndex, int slotIndex) {
+    if (bagIndex < 0 || bagIndex >= inventory.NUM_BAG_SLOTS) return;
+    if (slotIndex < 0 || slotIndex >= inventory.getBagSize(bagIndex)) return;
+    if (inventory.getBagSlot(bagIndex, slotIndex).empty()) return;
+    if (state != WorldState::IN_WORLD || !socket) return;
+    uint8_t wowBag = static_cast<uint8_t>(19 + bagIndex);
+    auto packet = OpenItemPacket::build(wowBag, static_cast<uint8_t>(slotIndex));
+    LOG_INFO("openItemInBag: CMSG_OPEN_ITEM bag=", (int)wowBag, " slot=", slotIndex);
+    socket->send(packet);
+}
+
 void GameHandler::useItemById(uint32_t itemId) {
     if (itemId == 0) return;
     LOG_DEBUG("useItemById: searching for itemId=", itemId);

src/game/world_packets.cpp

@@ -4271,6 +4271,13 @@ network::Packet UseItemPacket::build(uint8_t bagIndex, uint8_t slotIndex, uint64
     return packet;
 }
 
+network::Packet OpenItemPacket::build(uint8_t bagIndex, uint8_t slotIndex) {
+    network::Packet packet(wireOpcode(Opcode::CMSG_OPEN_ITEM));
+    packet.writeUInt8(bagIndex);
+    packet.writeUInt8(slotIndex);
+    return packet;
+}
+
 network::Packet AutoEquipItemPacket::build(uint8_t srcBag, uint8_t srcSlot) {
     network::Packet packet(wireOpcode(Opcode::CMSG_AUTOEQUIP_ITEM));
     packet.writeUInt8(srcBag);

src/ui/inventory_screen.cpp

@@ -2356,7 +2356,14 @@ void InventoryScreen::renderItemSlot(game::Inventory& inventory, const game::Ite
                 } else if (item.inventoryType > 0) {
                     gameHandler_->autoEquipItemBySlot(backpackIndex);
                 } else {
-                    gameHandler_->useItemBySlot(backpackIndex);
+                    // itemClass==1 (Container) with inventoryType==0 means a lockbox;
+                    // use CMSG_OPEN_ITEM so the server checks keyring automatically.
+                    auto* info = gameHandler_->getItemInfo(item.itemId);
+                    if (info && info->valid && info->itemClass == 1) {
+                        gameHandler_->openItemBySlot(backpackIndex);
+                    } else {
+                        gameHandler_->useItemBySlot(backpackIndex);
+                    }
                 }
             } else if (kind == SlotKind::BACKPACK && isBagSlot) {
                 LOG_INFO("Right-click bag item: name='", item.name,
@@ -2369,7 +2376,12 @@ void InventoryScreen::renderItemSlot(game::Inventory& inventory, const game::Ite
                 } else if (item.inventoryType > 0) {
                     gameHandler_->autoEquipItemInBag(bagIndex, bagSlotIndex);
                 } else {
-                    gameHandler_->useItemInBag(bagIndex, bagSlotIndex);
+                    auto* info = gameHandler_->getItemInfo(item.itemId);
+                    if (info && info->valid && info->itemClass == 1) {
+                        gameHandler_->openItemInBag(bagIndex, bagSlotIndex);
+                    } else {
+                        gameHandler_->useItemInBag(bagIndex, bagSlotIndex);
+                    }
                 }
             }
         }