refactor(chat): decompose into modular architecture, add GM commands, fix protocol

- Extract ChatPanel monolith into 15+ focused modules under ui/chat/
  (ChatInput, ChatTabManager, ChatTabCompleter, ChatMarkupParser,
  ChatMarkupRenderer, ChatCommandRegistry, ChatBubbleManager,
  ChatSettings, MacroEvaluator, GameStateAdapter, InputModifierAdapter)
- Split 2700-line chat_panel_commands.cpp into 11 command modules
- Add GM command handling: 190-command data table, dot-prefix interception,
  tab-completion, /gmhelp with category filter
- Fix ChatType enum to match WoW wire protocol (SAY=0x01 not 0x00);
  values 0x00-0x1B shared across Vanilla/TBC/WotLK
- Fix BG_SYSTEM_* values from 82-84 (UB in bitmask shifts) to 0x24-0x26
- Fix infinite Enter key loop after teleport (disable TOGGLE_CHAT repeat,
  add 2-frame input cooldown)
- Add tests: chat_markup_parser, chat_tab_completer, gm_commands,
  macro_evaluator

Signed-off-by: Pavel Okhlopkov <pavel.okhlopkov@flant.com>

include/ui/chat/chat_bubble_manager.hpp

@@ -0,0 +1,46 @@
+#pragma once
+
+#include "ui/ui_services.hpp"
+#include <cstdint>
+#include <string>
+#include <vector>
+
+namespace wowee {
+namespace game { class GameHandler; }
+namespace ui {
+
+/**
+ * Manages 3D-projected chat bubbles above entities.
+ *
+ * Extracted from ChatPanel (Phase 1.4 of chat_panel_ref.md).
+ * Owns bubble lifecycle: add, update (tick), render (ImGui overlay).
+ */
+class ChatBubbleManager {
+public:
+    /** Add or replace a bubble for the given entity. */
+    void addBubble(uint64_t senderGuid, const std::string& message, bool isYell);
+
+    /** Render and tick all active bubbles (projects to screen via camera). */
+    void render(game::GameHandler& gameHandler, const UIServices& services);
+
+    /** Register the chat-bubble callback on GameHandler (call once per session). */
+    void setupCallback(game::GameHandler& gameHandler);
+
+    bool empty() const { return bubbles_.empty(); }
+
+private:
+    struct ChatBubble {
+        uint64_t senderGuid = 0;
+        std::string message;
+        float timeRemaining = 0.0f;
+        float totalDuration = 0.0f;
+        bool isYell = false;
+    };
+    std::vector<ChatBubble> bubbles_;
+    bool callbackSet_ = false;
+
+    static constexpr size_t kMaxBubbles = 10;
+};
+
+} // namespace ui
+} // namespace wowee