chore(game-ui): extract chat panel into dedicated UI module

- moved chat panel logic out of `game_screen` into `chat_panel`
- added chat_panel.hpp and chat_panel.cpp
- updated game_screen.hpp and game_screen.cpp to integrate new `ChatPanel` component
- updated build config in CMakeLists.txt to include new UI module sources

include/ui/chat_panel.hpp

@@ -0,0 +1,194 @@
+#pragma once
+
+#include "game/game_handler.hpp"
+#include <vulkan/vulkan.h>
+#include <imgui.h>
+#include <string>
+#include <vector>
+#include <functional>
+
+namespace wowee {
+namespace pipeline { class AssetManager; }
+namespace rendering { class Renderer; }
+namespace ui {
+
+class InventoryScreen;
+class SpellbookScreen;
+class QuestLogScreen;
+
+/**
+ * Self-contained chat UI panel extracted from GameScreen.
+ *
+ * Owns all chat state: input buffer, sent-history, tab filtering,
+ * slash-command parsing, chat bubbles, and chat-related settings.
+ */
+class ChatPanel {
+public:
+    ChatPanel();
+
+    // ---- Main entry points (called by GameScreen) ----
+
+    /**
+     * Render the chat window (tabs, history, input, etc.)
+     */
+    void render(game::GameHandler& gameHandler,
+               InventoryScreen& inventoryScreen,
+               SpellbookScreen& spellbookScreen,
+               QuestLogScreen& questLogScreen);
+
+    /**
+     * Render 3D-projected chat bubbles above entities.
+     */
+    void renderBubbles(game::GameHandler& gameHandler);
+
+    /**
+     * Register one-shot callbacks on GameHandler (call once per session).
+     * Sets up the chat-bubble callback.
+     */
+    void setupCallbacks(game::GameHandler& gameHandler);
+
+    // ---- Input helpers (called by GameScreen keybind handling) ----
+
+    bool isChatInputActive() const { return chatInputActive_; }
+
+    /** Insert a spell / item link into the chat input buffer (shift-click). */
+    void insertChatLink(const std::string& link);
+
+    /** Activate the input field with a leading '/' (slash key). */
+    void activateSlashInput();
+
+    /** Activate (focus) the input field (Enter key). */
+    void activateInput();
+
+    /** Request that the chat input be focused next frame. */
+    void requestRefocus() { refocusChatInput_ = true; }
+
+    /** Set up a whisper to the given player name and focus input. */
+    void setWhisperTarget(const std::string& name);
+
+    /** Execute a macro body (one line per 'click'). */
+    void executeMacroText(game::GameHandler& gameHandler,
+                          InventoryScreen& inventoryScreen,
+                          SpellbookScreen& spellbookScreen,
+                          QuestLogScreen& questLogScreen,
+                          const std::string& macroText);
+
+    // ---- Slash-command side-effects ----
+    // GameScreen reads these each frame, then clears them.
+
+    struct SlashCommands {
+        bool showInspect   = false;
+        bool toggleThreat  = false;
+        bool showBgScore   = false;
+        bool showGmTicket  = false;
+        bool showWho       = false;
+        bool toggleCombatLog = false;
+        bool takeScreenshot = false;
+    };
+
+    /** Return accumulated slash-command flags and reset them. */
+    SlashCommands consumeSlashCommands();
+
+    // ---- Chat settings (read/written by GameScreen save/load & settings tab) ----
+
+    bool  chatShowTimestamps  = false;
+    int   chatFontSize        = 1;   // 0=small, 1=medium, 2=large
+    bool  chatAutoJoinGeneral = true;
+    bool  chatAutoJoinTrade   = true;
+    bool  chatAutoJoinLocalDefense = true;
+    bool  chatAutoJoinLFG     = true;
+    bool  chatAutoJoinLocal   = true;
+    int   activeChatTab       = 0;
+
+    /** Spell icon lookup callback — set by GameScreen each frame before render(). */
+    std::function<VkDescriptorSet(uint32_t, pipeline::AssetManager*)> getSpellIcon;
+
+    /** Render the "Chat" tab inside the Settings window. */
+    void renderSettingsTab(std::function<void()> saveSettingsFn);
+
+    /** Reset all chat settings to defaults. */
+    void restoreDefaults();
+
+    /** Replace $g/$G and $n/$N gender/name placeholders in quest/chat text. */
+    std::string replaceGenderPlaceholders(const std::string& text, game::GameHandler& gameHandler);
+
+private:
+    // ---- Chat input state ----
+    char chatInputBuffer_[512] = "";
+    char whisperTargetBuffer_[256] = "";
+    bool chatInputActive_ = false;
+    int  selectedChatType_ = 0;  // 0=SAY .. 10=CHANNEL
+    int  lastChatType_     = 0;
+    int  selectedChannelIdx_ = 0;
+    bool chatInputMoveCursorToEnd_ = false;
+    bool refocusChatInput_ = false;
+
+    // Sent-message history (Up/Down arrow recall)
+    std::vector<std::string> chatSentHistory_;
+    int chatHistoryIdx_ = -1;
+
+    // Macro stop flag
+    bool macroStopped_ = false;
+
+    // Tab-completion state
+    std::string chatTabPrefix_;
+    std::vector<std::string> chatTabMatches_;
+    int chatTabMatchIdx_ = -1;
+
+    // Mention notification
+    size_t chatMentionSeenCount_ = 0;
+
+    // ---- Chat tabs ----
+    struct ChatTab {
+        std::string name;
+        uint64_t typeMask;
+    };
+    std::vector<ChatTab> chatTabs_;
+    std::vector<int> chatTabUnread_;
+    size_t chatTabSeenCount_ = 0;
+
+    void initChatTabs();
+    bool shouldShowMessage(const game::MessageChatData& msg, int tabIndex) const;
+
+    // ---- Chat window visual state ----
+    bool  chatScrolledUp_          = false;
+    bool  chatForceScrollToBottom_ = false;
+    bool  chatWindowLocked_        = true;
+    ImVec2 chatWindowPos_          = ImVec2(0.0f, 0.0f);
+    bool  chatWindowPosInit_       = false;
+
+    // ---- Chat bubbles ----
+    struct ChatBubble {
+        uint64_t senderGuid   = 0;
+        std::string message;
+        float timeRemaining   = 0.0f;
+        float totalDuration   = 0.0f;
+        bool isYell           = false;
+    };
+    std::vector<ChatBubble> chatBubbles_;
+    bool chatBubbleCallbackSet_ = false;
+
+    // ---- Whisper toast state (populated in render, rendered by GameScreen/ToastManager) ----
+    // Whisper scanning lives here because it's tightly coupled to chat history iteration.
+    size_t whisperSeenCount_ = 0;
+
+    // ---- Helpers ----
+    void sendChatMessage(game::GameHandler& gameHandler,
+                         InventoryScreen& inventoryScreen,
+                         SpellbookScreen& spellbookScreen,
+                         QuestLogScreen& questLogScreen);
+    const char* getChatTypeName(game::ChatType type) const;
+    ImVec4 getChatTypeColor(game::ChatType type) const;
+
+    // Cached game handler for input callback (set each frame in render)
+    game::GameHandler* cachedGameHandler_ = nullptr;
+
+    // Join channel input buffer
+    char joinChannelBuffer_[128] = "";
+
+    // Slash command flags (accumulated, consumed by GameScreen)
+    SlashCommands slashCmds_;
+};
+
+} // namespace ui
+} // namespace wowee