Restructure inventory UI, add vendor selling, camera intro on all spawns, and quest log

Split inventory into bags-only (B key) and character screen (C key). Vendor window
auto-opens bags with sell prices on hover and right-click to sell. Add camera intro
pan on all login/spawn/teleport/hearthstone events and idle orbit after 2 minutes.
Add quest log UI, SMSG_MONSTER_MOVE handling, deferred creature spawn queue, and
creature fade-in/movement interpolation for online mode.

include/game/game_handler.hpp

@@ -294,6 +294,11 @@ public:
     using CreatureDespawnCallback = std::function<void(uint64_t guid)>;
     void setCreatureDespawnCallback(CreatureDespawnCallback cb) { creatureDespawnCallback_ = std::move(cb); }
 
+    // Creature move callback (online mode - triggered by SMSG_MONSTER_MOVE)
+    // Parameters: guid, x, y, z (canonical), duration_ms (0 = instant)
+    using CreatureMoveCallback = std::function<void(uint64_t guid, float x, float y, float z, uint32_t durationMs)>;
+    void setCreatureMoveCallback(CreatureMoveCallback cb) { creatureMoveCallback_ = std::move(cb); }
+
     // Cooldowns
     float getSpellCooldown(uint32_t spellId) const;
 
@@ -330,17 +335,33 @@ public:
     bool isQuestDetailsOpen() const { return questDetailsOpen; }
     const QuestDetailsData& getQuestDetails() const { return currentQuestDetails; }
 
+    // Quest log
+    struct QuestLogEntry {
+        uint32_t questId = 0;
+        std::string title;
+        std::string objectives;
+        bool complete = false;
+    };
+    const std::vector<QuestLogEntry>& getQuestLog() const { return questLog_; }
+    void abandonQuest(uint32_t questId);
+
     // Vendor
     void openVendor(uint64_t npcGuid);
     void closeVendor();
     void buyItem(uint64_t vendorGuid, uint32_t itemId, uint32_t slot, uint8_t count);
     void sellItem(uint64_t vendorGuid, uint64_t itemGuid, uint8_t count);
+    void sellItemBySlot(int backpackIndex);
     bool isVendorWindowOpen() const { return vendorWindowOpen; }
     const ListInventoryData& getVendorItems() const { return currentVendorItems; }
     const ItemQueryResponseData* getItemInfo(uint32_t itemId) const {
         auto it = itemInfoCache_.find(itemId);
         return (it != itemInfoCache_.end()) ? &it->second : nullptr;
     }
+    uint64_t getBackpackItemGuid(int index) const {
+        if (index < 0 || index >= static_cast<int>(backpackSlotGuids_.size())) return 0;
+        return backpackSlotGuids_[index];
+    }
+    uint64_t getVendorGuid() const { return currentVendorItems.vendorGuid; }
 
     /**
      * Set callbacks
@@ -464,6 +485,9 @@ private:
     // ---- XP handler ----
     void handleXpGain(network::Packet& packet);
 
+    // ---- Creature movement handler ----
+    void handleMonsterMove(network::Packet& packet);
+
     // ---- Phase 5 handlers ----
     void handleLootResponse(network::Packet& packet);
     void handleLootReleaseResponse(network::Packet& packet);
@@ -580,6 +604,7 @@ private:
     WorldEntryCallback worldEntryCallback_;
     CreatureSpawnCallback creatureSpawnCallback_;
     CreatureDespawnCallback creatureDespawnCallback_;
+    CreatureMoveCallback creatureMoveCallback_;
     std::vector<uint32_t> knownSpells;
     std::unordered_map<uint32_t, float> spellCooldowns;    // spellId -> remaining seconds
     uint8_t castCount = 0;
@@ -616,6 +641,9 @@ private:
     bool questDetailsOpen = false;
     QuestDetailsData currentQuestDetails;
 
+    // Quest log
+    std::vector<QuestLogEntry> questLog_;
+
     // Vendor
     bool vendorWindowOpen = false;
     ListInventoryData currentVendorItems;

include/game/opcodes.hpp

@@ -68,6 +68,9 @@ enum class Opcode : uint16_t {
     // ---- XP ----
     SMSG_LOG_XPGAIN                  = 0x1D0,
 
+    // ---- Creature Movement ----
+    SMSG_MONSTER_MOVE                = 0x0DD,
+
     // ---- Phase 2: Combat Core ----
     CMSG_ATTACKSWING                 = 0x141,
     CMSG_ATTACKSTOP                  = 0x142,
@@ -146,6 +149,7 @@ enum class Opcode : uint16_t {
     SMSG_QUESTGIVER_OFFER_REWARD     = 0x18D,
     CMSG_QUESTGIVER_CHOOSE_REWARD    = 0x18E,
     SMSG_QUESTGIVER_QUEST_COMPLETE   = 0x191,
+    CMSG_QUESTLOG_REMOVE_QUEST       = 0x194,
 
     // ---- Phase 5: Vendor ----
     CMSG_LIST_INVENTORY              = 0x19E,

include/game/world_packets.hpp

@@ -740,6 +740,7 @@ struct ItemQueryResponseData {
     int32_t agility = 0;
     int32_t intellect = 0;
     int32_t spirit = 0;
+    uint32_t sellPrice = 0;
     std::string subclassName;
     bool valid = false;
 };
@@ -754,6 +755,25 @@ public:
 // Phase 2: Combat Core
 // ============================================================
 
+/** SMSG_MONSTER_MOVE data */
+struct MonsterMoveData {
+    uint64_t guid = 0;
+    float x = 0, y = 0, z = 0;  // Current position (server coords)
+    uint8_t moveType = 0;  // 0=Normal, 1=Stop, 2=FacingSpot, 3=FacingTarget, 4=FacingAngle
+    float facingAngle = 0;
+    uint64_t facingTarget = 0;
+    uint32_t splineFlags = 0;
+    uint32_t duration = 0;
+    // Destination (final point of the spline, server coords)
+    float destX = 0, destY = 0, destZ = 0;
+    bool hasDest = false;
+};
+
+class MonsterMoveParser {
+public:
+    static bool parse(network::Packet& packet, MonsterMoveData& data);
+};
+
 /** CMSG_ATTACKSWING packet builder */
 class AttackSwingPacket {
 public: