fix: right-clicking a quest-starting item now opens the quest offer dialog

Items with startQuestId != 0 were calling useItemBySlot()/useItemInBag()
which sends CMSG_USE_ITEM — but quest-starting items have no on-use spell,
so the server silently ignored the packet and no quest dialog appeared.

Fix:
- offerQuestFromItem(itemGuid, questId): sends CMSG_QUESTGIVER_QUERY_QUEST
  with the item's own GUID as the questgiver GUID. The server responds with
  SMSG_QUESTGIVER_QUEST_DETAILS which handleQuestDetails() already picks up
  and opens the Accept/Decline dialog with full rewards/description.
- getBagItemGuid(bagIndex, slotIndex): resolves the per-slot item GUID from
  the bag's containerContents_ map (mirrors the logic inside useItemInBag).
- inventory_screen.cpp right-click handler: checks item.startQuestId != 0
  before the equip/use branch; if set, resolves item GUID and calls
  offerQuestFromItem. Works for both backpack slots and bag slots.

include/game/game_handler.hpp

@@ -1460,6 +1460,9 @@ public:
     void acceptQuest();
     void declineQuest();
     void closeGossip();
+    // Quest-starting items: right-click triggers quest offer dialog via questgiver protocol
+    void offerQuestFromItem(uint64_t itemGuid, uint32_t questId);
+    uint64_t getBagItemGuid(int bagIndex, int slotIndex) const;
     bool isGossipWindowOpen() const { return gossipWindowOpen; }
     const GossipMessageData& getCurrentGossip() const { return currentGossip; }
     bool isQuestDetailsOpen() {

src/game/game_handler.cpp

@@ -20552,6 +20552,34 @@ void GameHandler::closeGossip() {
     currentGossip = GossipMessageData{};
 }
 
+void GameHandler::offerQuestFromItem(uint64_t itemGuid, uint32_t questId) {
+    if (state != WorldState::IN_WORLD || !socket) return;
+    if (itemGuid == 0 || questId == 0) {
+        addSystemChatMessage("Cannot start quest right now.");
+        return;
+    }
+    // Send CMSG_QUESTGIVER_QUERY_QUEST with the item GUID as the "questgiver."
+    // The server responds with SMSG_QUESTGIVER_QUEST_DETAILS which handleQuestDetails()
+    // picks up and opens the Accept/Decline dialog.
+    auto queryPkt = packetParsers_
+        ? packetParsers_->buildQueryQuestPacket(itemGuid, questId)
+        : QuestgiverQueryQuestPacket::build(itemGuid, questId);
+    socket->send(queryPkt);
+    LOG_INFO("offerQuestFromItem: itemGuid=0x", std::hex, itemGuid, std::dec,
+             " questId=", questId);
+}
+
+uint64_t GameHandler::getBagItemGuid(int bagIndex, int slotIndex) const {
+    if (bagIndex < 0 || bagIndex >= inventory.NUM_BAG_SLOTS) return 0;
+    if (slotIndex < 0) return 0;
+    uint64_t bagGuid = equipSlotGuids_[19 + bagIndex];
+    if (bagGuid == 0) return 0;
+    auto it = containerContents_.find(bagGuid);
+    if (it == containerContents_.end()) return 0;
+    if (slotIndex >= static_cast<int>(it->second.numSlots)) return 0;
+    return it->second.slotGuids[slotIndex];
+}
+
 void GameHandler::openVendor(uint64_t npcGuid) {
     if (state != WorldState::IN_WORLD || !socket) return;
     buybackItems_.clear();

src/ui/inventory_screen.cpp

@@ -2335,8 +2335,12 @@ void InventoryScreen::renderItemSlot(game::Inventory& inventory, const game::Ite
             } else if (kind == SlotKind::BACKPACK && backpackIndex >= 0) {
                 LOG_INFO("Right-click backpack item: name='", item.name,
                          "' inventoryType=", (int)item.inventoryType,
-                         " itemId=", item.itemId);
+                         " itemId=", item.itemId,
-                if (item.inventoryType > 0) {
+                         " startQuestId=", item.startQuestId);
+                if (item.startQuestId != 0) {
+                    uint64_t iGuid = gameHandler_->getBackpackItemGuid(backpackIndex);
+                    gameHandler_->offerQuestFromItem(iGuid, item.startQuestId);
+                } else if (item.inventoryType > 0) {
                     gameHandler_->autoEquipItemBySlot(backpackIndex);
                 } else {
                     gameHandler_->useItemBySlot(backpackIndex);
@@ -2344,8 +2348,12 @@ void InventoryScreen::renderItemSlot(game::Inventory& inventory, const game::Ite
             } else if (kind == SlotKind::BACKPACK && isBagSlot) {
                 LOG_INFO("Right-click bag item: name='", item.name,
                          "' inventoryType=", (int)item.inventoryType,
-                         " bagIndex=", bagIndex, " slotIndex=", bagSlotIndex);
+                         " bagIndex=", bagIndex, " slotIndex=", bagSlotIndex,
-                if (item.inventoryType > 0) {
+                         " startQuestId=", item.startQuestId);
+                if (item.startQuestId != 0) {
+                    uint64_t iGuid = gameHandler_->getBagItemGuid(bagIndex, bagSlotIndex);
+                    gameHandler_->offerQuestFromItem(iGuid, item.startQuestId);
+                } else if (item.inventoryType > 0) {
                     gameHandler_->autoEquipItemInBag(bagIndex, bagSlotIndex);
                 } else {
                     gameHandler_->useItemInBag(bagIndex, bagSlotIndex);