Feat: Support viewing active window via online-host popup menu

client/ScreenSpy.h

@@ -95,7 +95,8 @@ protected:
 
     BOOL					m_bVirtualPaint;// 是否虚拟绘制
     EnumHwndsPrintData		m_data;
-    HWND                    m_hTargetWnd = NULL; // 窗口捕获目标（NULL=全屏）
+    HWND                    m_hTargetWnd = NULL;       // 窗口捕获目标（NULL=全屏）
+    bool                    m_bDynamicForeground = false; // true=每帧跟踪前景窗口（由 sentinel=-1 触发）
     int                     m_ShadowLeft = 0;   // DWM 阴影左偏移（frameRc.left - fullRc.left），帧间缓存
     int                     m_ShadowTop  = 0;   // DWM 阴影上偏移（frameRc.top  - fullRc.top），帧间缓存
     int                     m_CachedWndW = 0;   // 上帧 GetWindowRect 宽度，用于检测 resize 无需每帧调 DWM
@@ -106,7 +107,7 @@ protected:
 
 public:
     CScreenSpy(ULONG ulbiBitCount, BYTE algo, BOOL vDesk = FALSE, int gop = DEFAULT_GOP, BOOL all = FALSE,
-        int level = LEVEL_H264_SOFT, RECT rc = {0}, BOOL switchScreen = TRUE, HWND hwnd = NULL);
+        int level = LEVEL_H264_SOFT, RECT rc = {0}, BOOL switchScreen = TRUE, HWND hwnd = NULL, bool dynamicFg = false);
 
     virtual HWND GetTargetWindow() const override { return m_hTargetWnd; }