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_markup_renderer.hpp

@@ -0,0 +1,62 @@
+#pragma once
+
+#include "ui/chat/chat_markup_parser.hpp"
+#include "ui/ui_services.hpp"
+#include <vulkan/vulkan.h>
+#include <functional>
+#include <cstdint>
+#include <string>
+#include <vector>
+
+namespace wowee {
+namespace game { class GameHandler; }
+namespace pipeline { class AssetManager; }
+namespace ui {
+
+class InventoryScreen;
+class SpellbookScreen;
+class QuestLogScreen;
+
+/**
+ * Context needed by the renderer to display links, tooltips, and icons.
+ */
+struct MarkupRenderContext {
+    game::GameHandler*  gameHandler   = nullptr;
+    InventoryScreen*    inventory     = nullptr;
+    SpellbookScreen*    spellbook     = nullptr;
+    QuestLogScreen*     questLog      = nullptr;
+    pipeline::AssetManager* assetMgr  = nullptr;
+    // Spell icon callback — same as ChatPanel::getSpellIcon
+    std::function<VkDescriptorSet(uint32_t, pipeline::AssetManager*)> getSpellIcon;
+    // Chat input buffer for shift-click link insertion
+    char*   chatInputBuffer   = nullptr;
+    size_t  chatInputBufSize  = 0;
+    bool*   moveCursorToEnd   = nullptr;
+};
+
+/**
+ * Renders parsed ChatSegments via ImGui.
+ *
+ * Extracted from ChatPanel::render() inline lambdas (Phase 2.2 of chat_panel_ref.md).
+ * Handles: colored text, item/spell/quest/achievement link tooltips+icons,
+ * URL click-to-open, shift-click link insertion.
+ */
+class ChatMarkupRenderer {
+public:
+    /** Render a list of segments with ImGui. baseColor is the message-type color. */
+    void render(const std::vector<ChatSegment>& segments,
+                const ImVec4& baseColor,
+                const MarkupRenderContext& ctx) const;
+
+    /**
+     * Render a full item tooltip for the given item entry.
+     * Extracted from the renderItemLinkTooltip inline lambda.
+     */
+    static void renderItemTooltip(uint32_t itemEntry,
+                                  game::GameHandler& gameHandler,
+                                  InventoryScreen& inventoryScreen,
+                                  pipeline::AssetManager* assetMgr);
+};
+
+} // namespace ui
+} // namespace wowee