Fix: Skip video capture when camera fails to open

CCaptureVideo::Open now returns S_FALSE when BindVideoFilter cannot bind a capture device, instead of S_OK. CVideoManager records the result in m_bVideoOpened and exits WorkThread before SendBitMapInfor, so a host without a webcam no longer sends a 0x0 BITMAPINFO to the controller.

Co-Authored-By: deepseek-v4-pro

client/CaptureVideo.cpp

@@ -46,13 +46,15 @@ CCaptureVideo::~CCaptureVideo()
 HRESULT CCaptureVideo::Open(int iDeviceID,int iPress)
 {
     Mprintf("CCaptureVideo call Open\n");
-    HRESULT hResult = S_OK;
+    HRESULT hResult = S_FALSE;
     do {
         hResult = InitCaptureGraphBuilder();
         if (FAILED(hResult))
             break;
-        if(!BindVideoFilter(iDeviceID, &m_pBF))
+        if (!BindVideoFilter(iDeviceID, &m_pBF)) {
+            hResult = S_FALSE;
             break;
+        }
 
         hResult = m_pGB->AddFilter(m_pBF, L"Capture Filter");