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/ui/game_screen.hpp

@@ -4,6 +4,7 @@
 #include "game/inventory.hpp"
 #include "rendering/world_map.hpp"
 #include "ui/inventory_screen.hpp"
+#include "ui/quest_log_screen.hpp"
 #include "ui/spellbook_screen.hpp"
 #include <imgui.h>
 #include <string>
@@ -143,6 +144,7 @@ private:
     void renderWorldMap(game::GameHandler& gameHandler);
 
     InventoryScreen inventoryScreen;
+    QuestLogScreen questLogScreen;
     SpellbookScreen spellbookScreen;
     rendering::WorldMap worldMap;
 

include/ui/inventory_screen.hpp

@@ -1,18 +1,36 @@
 #pragma once
 
 #include "game/inventory.hpp"
+#include "game/world_packets.hpp"
 #include <imgui.h>
+#include <functional>
 
 namespace wowee {
+namespace game { class GameHandler; }
 namespace ui {
 
 class InventoryScreen {
 public:
+    /// Render bags window (B key). Positioned at bottom of screen.
     void render(game::Inventory& inventory, uint64_t moneyCopper);
+
+    /// Render character screen (C key). Standalone equipment window.
+    void renderCharacterScreen(game::Inventory& inventory);
+
     bool isOpen() const { return open; }
     void toggle() { open = !open; }
     void setOpen(bool o) { open = o; }
 
+    bool isCharacterOpen() const { return characterOpen; }
+    void toggleCharacter() { characterOpen = !characterOpen; }
+    void setCharacterOpen(bool o) { characterOpen = o; }
+
+    /// Enable vendor mode: right-clicking bag items sells them.
+    void setVendorMode(bool enabled, game::GameHandler* handler) {
+        vendorMode_ = enabled;
+        gameHandler_ = handler;
+    }
+
     /// Returns true if equipment changed since last call, and clears the flag.
     bool consumeEquipmentDirty() { bool d = equipmentDirty; equipmentDirty = false; return d; }
     /// Returns true if any inventory slot changed since last call, and clears the flag.
@@ -20,10 +38,16 @@ public:
 
 private:
     bool open = false;
+    bool characterOpen = false;
     bool bKeyWasDown = false;
+    bool cKeyWasDown = false;
     bool equipmentDirty = false;
     bool inventoryDirty = false;
 
+    // Vendor sell mode
+    bool vendorMode_ = false;
+    game::GameHandler* gameHandler_ = nullptr;
+
     // Drag-and-drop held item state
     bool holdingItem = false;
     game::ItemDef heldItem;

include/ui/quest_log_screen.hpp

@@ -0,0 +1,21 @@
+#pragma once
+
+#include "game/game_handler.hpp"
+#include <imgui.h>
+
+namespace wowee { namespace ui {
+
+class QuestLogScreen {
+public:
+    void render(game::GameHandler& gameHandler);
+    bool isOpen() const { return open; }
+    void toggle() { open = !open; }
+    void setOpen(bool o) { open = o; }
+
+private:
+    bool open = false;
+    bool lKeyWasDown = false;
+    int selectedIndex = -1;
+};
+
+}} // namespace wowee::ui