refactor: clean up verbose migration comments

Remove redundant Qt6 migration comments that restate obvious API changes:
- QtConcurrent::run parameter order explanations (preserved where lambda wrapping needed)
- QStringRef/QStringView API changes (shortened to essential info)
- QComboBox::activated signal signature change
- QMap::unite() removal semantics
- QAction include path change
- QMouseEvent/QWheelEvent position() API
- QList/QVector equivalence in Qt6
- QFuture continuation API
- Code generation comments

Preserved comments explaining non-obvious Qt6 behavior or necessary
API migration details.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

qt6-after/qt6-migrated-legatus/Lts/Services/AudioVideoManagement/av_socket.cpp

@@ -104,8 +104,7 @@ void AVSocket::onConnectToAVS()
             this, &AVSocket::onDisconnected);
     connect(m_avsSocket, &QTcpSocket::connected,
             this, [this] {m_bErrorInTcpComWarnedOnce = false;});
-    // Qt6: QAbstractSocket::error() (the getter/signal overload pair) was
-    // replaced by the errorOccurred signal.
+    // errorOccurred signal replaces error() getter/signal
     connect(m_avsSocket, &QAbstractSocket::errorOccurred,
             this, &AVSocket::onError);
     connect(m_avsSocket, &QTcpSocket::readyRead,