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/Common.cpp

@@ -5,6 +5,7 @@
 #include "ScreenManager.h"
 #include "FileManager.h"
 #include "TalkManager.h"
+#include "ChatManager.h"
 #include "ShellManager.h"
 #include "SystemManager.h"
 #include "ConPTYManager.h"
@@ -101,6 +102,11 @@ DWORD WINAPI LoopTalkManager(LPVOID lParam)
     return LoopManager<CTalkManager, 0>(lParam);
 }
 
+DWORD WINAPI LoopChatManager(LPVOID lParam)
+{
+    return LoopManager<CChatManager, 0>(lParam);
+}
+
 DWORD WINAPI LoopShellManager(LPVOID lParam)
 {
     // Use ConPTY for xterm.js terminal on Windows 10 1809+, fallback to legacy pipe