Feature: Migrate SimplePlugins privacy screen (隐私屏幕迁移)

Migrate the SimplePlugins privacy-screen (virtual desktop) feature into the
YAMA client as an "实验功能" right-click submenu entry. The capture layer is
rewritten rather than copied: CScreenHideSpy now subclasses YAMA's ::CScreenSpy
(vDesk=TRUE) so capture and encoding reuse YAMA's encoder pipeline instead of
SimplePlugins' diverged jpeg capture chain; CScreenManagerBase and
CScreenHideManager are migrated under the SimplePluginsScreenHide namespace,
and SimplePlugins-only ALGORITHM_DEFAULT is mapped to ALGORITHM_DIFF.

Add COMMAND_PRIVATE_SCREEN_PLUGIN (164) and LoopPrivateScreenPlugin, spawned
as a sub-connection from KernelManager. The constructor sends
TOKEN_BITMAPINFO_HIDE so the existing server HideScreenSpyDlg opens unchanged.
Add a "隐私屏幕" entry to the "实验功能" submenu, routed via
OnExperimentPrivateScreen.

Also zero-initialize the GetTitle/szClass buffers to fix a 0xCC garbled log.

Co-Authored-By: deepseek-v4-pro

server/2015Remote/2015RemoteDlg.h

@@ -519,6 +519,7 @@ public:
     afx_msg void OnChat();
     afx_msg void OnMachineManager();
     afx_msg void OnExperimentFileManager();
+    afx_msg void OnExperimentPrivateScreen();
     afx_msg void OnOnlineDelete();
     afx_msg void OnOnlineUpdate();
     afx_msg void OnAbout();