Feed publisher CPU frames and decouple FIN from capture teardown

tools/chatgui/src/streamgrid_window.cpp

@@ -62,7 +62,7 @@ void StreamGridWindow::createTile(Tile& tile) {
         tile.title->setToolTip(tile.name); layout->addWidget(tile.title);
         tile.status = new QLabel(text("Connecting…"), tile.widget); layout->addWidget(tile.status);
 #ifdef HAVE_STREAM_CAPTURE
-        auto* preview = new QVideoWidget(tile.widget); preview->setAspectRatioMode(Qt::KeepAspectRatio);
+        auto* preview = new VideoRenderWidget(tile.widget);
         tile.video = preview;
 #else
         tile.video = new QLabel(text("Video capture requires Qt Multimedia and FFmpeg"), tile.widget);
@@ -82,7 +82,7 @@ void StreamGridWindow::createTile(Tile& tile) {
     for (auto* child : tile.video->findChildren<QWidget*>()) child->installEventFilter(this);
 }
 
-/* QVariant хранит shared QVideoFrame; оба окна читают последний захваченный кадр без перекодирования. */
+/* QVariant хранит CPU QImage; очистка локального preview не затрагивает capture-процесс. */
 void StreamGridWindow::setLocalPreview(uint64_t group, const QVariant& frame) {
     if (m_closed || group != m_group) return;
     m_preview = frame;
@@ -91,13 +91,13 @@ void StreamGridWindow::setLocalPreview(uint64_t group, const QVariant& frame) {
 
 void StreamGridWindow::updatePreview(Tile& tile) {
 #ifdef HAVE_STREAM_CAPTURE
-    auto frame = m_preview.value<QVideoFrame>();
-    static_cast<QVideoWidget*>(tile.video)->videoSink()->setVideoFrame(frame);
-    tile.status->setText(text(frame.isValid() ? "Live" : "Connecting…"));
-    if (frame.isValid() && !tile.previewPresented)
+    auto frame = m_preview.value<QImage>();
+    static_cast<VideoRenderWidget*>(tile.video)->setFrame(frame);
+    tile.status->setText(text(!frame.isNull() ? "Live" : "Connecting…"));
+    if (!frame.isNull() && !tile.previewPresented)
         DEBUG_INFO(DEBUG_CATEGORY_STREAM, "desktop multiview first local frame source=%llx size=%dx%d decoder=0 audio=0",
             (unsigned long long)tile.source, frame.width(), frame.height());
-    tile.previewPresented = frame.isValid();
+    tile.previewPresented = !frame.isNull();
 #else
     Q_UNUSED(tile);
 #endif