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_input.hpp

@@ -0,0 +1,95 @@
+#pragma once
+
+#include <cstring>
+#include <string>
+#include <vector>
+
+namespace wowee {
+namespace ui {
+
+/**
+ * Chat input state: buffer, whisper target, sent-history, focus management.
+ *
+ * Extracted from ChatPanel (Phase 1.2 of chat_panel_ref.md).
+ * No UI or network dependencies — pure state management.
+ */
+class ChatInput {
+public:
+    // ---- Buffer access ----
+    char*       getBuffer()            { return buffer_; }
+    const char* getBuffer()      const { return buffer_; }
+    size_t      getBufferSize()  const { return sizeof(buffer_); }
+
+    char*       getWhisperBuffer()           { return whisperBuffer_; }
+    const char* getWhisperBuffer()     const { return whisperBuffer_; }
+    size_t      getWhisperBufferSize() const { return sizeof(whisperBuffer_); }
+
+    void clear()    { buffer_[0] = '\0'; }
+    bool isEmpty() const { return buffer_[0] == '\0'; }
+    std::string getText() const { return std::string(buffer_); }
+    void setText(const std::string& text) {
+        strncpy(buffer_, text.c_str(), sizeof(buffer_) - 1);
+        buffer_[sizeof(buffer_) - 1] = '\0';
+    }
+
+    // ---- Whisper target ----
+    std::string getWhisperTarget() const { return std::string(whisperBuffer_); }
+    void setWhisperTarget(const std::string& name) {
+        strncpy(whisperBuffer_, name.c_str(), sizeof(whisperBuffer_) - 1);
+        whisperBuffer_[sizeof(whisperBuffer_) - 1] = '\0';
+    }
+
+    // ---- Sent-message history (Up/Down arrow recall) ----
+    void pushToHistory(const std::string& msg);
+    std::string historyUp();
+    std::string historyDown();
+    void resetHistoryIndex() { historyIdx_ = -1; }
+    int getHistoryIndex() const { return historyIdx_; }
+    const std::vector<std::string>& getSentHistory() const { return sentHistory_; }
+
+    // ---- Focus state ----
+    bool isActive() const { return active_; }
+    void setActive(bool v) { active_ = v; }
+
+    bool shouldFocus() const { return focusRequested_; }
+    void requestFocus() { focusRequested_ = true; }
+    void clearFocusRequest() { focusRequested_ = false; }
+
+    bool shouldMoveCursorToEnd() const { return moveCursorToEnd_; }
+    void requestMoveCursorToEnd() { moveCursorToEnd_ = true; }
+    void clearMoveCursorToEnd() { moveCursorToEnd_ = false; }
+
+    // ---- Chat type selection ----
+    int  getSelectedChatType() const { return selectedChatType_; }
+    void setSelectedChatType(int t) { selectedChatType_ = t; }
+    int  getLastChatType() const { return lastChatType_; }
+    void setLastChatType(int t) { lastChatType_ = t; }
+    int  getSelectedChannelIdx() const { return selectedChannelIdx_; }
+    void setSelectedChannelIdx(int i) { selectedChannelIdx_ = i; }
+
+    // ---- Link insertion (shift-click) ----
+    void insertLink(const std::string& link);
+
+    // ---- Slash key activation ----
+    void activateSlashInput();
+
+private:
+    char buffer_[512]        = "";
+    char whisperBuffer_[256] = "";
+    bool active_             = false;
+    bool focusRequested_     = false;
+    bool moveCursorToEnd_    = false;
+
+    // Chat type dropdown state
+    int selectedChatType_   = 0;  // 0=SAY .. 10=CHANNEL
+    int lastChatType_       = 0;
+    int selectedChannelIdx_ = 0;
+
+    // Sent-message history
+    std::vector<std::string> sentHistory_;
+    int historyIdx_ = -1;
+    static constexpr int kMaxHistory = 50;
+};
+
+} // namespace ui
+} // namespace wowee