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

client/screenhide/ScreenHideSpy.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include "ScreenSpy.h"
+
+namespace SimplePluginsScreenHide {
+
+// 隐私屏幕捕获器。
+//
+// SimplePlugins 原版 CScreenHideSpy 基于其自带的旧 CScreenSpy/ScreenCapture 捕获链
+// （jpeg + CaptureFrame/BMP_JPG/ScanChangedRect），已与 YAMA 重写后的编码器捕获层
+// （ScreenCapture::GetNextScreenData + EncoderFactory）分叉，故此处改写为直接继承
+// YAMA 的 ::CScreenSpy，仅把 vDesk=TRUE（虚拟桌面）传入基类，捕获/编码全部复用基类。
+class CScreenHideSpy : public ::CScreenSpy
+{
+public:
+    CScreenHideSpy(int biBitCount = 32, int algo = ALGORITHM_DIFF)
+        : ::CScreenSpy((ULONG)biBitCount, (BYTE)algo, TRUE /* vDesk → m_bVirtualPaint */)
+    {
+    }
+};
+
+} // namespace SimplePluginsScreenHide