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/Tools/DataSampleReceiver/main.cpp

@@ -30,7 +30,6 @@ static QVector<DDSGeneric::TopicDescription> getAvailableTopicTypes() // get top
       return false;
 
     QMap<std::string,DDSGeneric::TopicDescription> topics = typePlugin->getDataTopics();
-    // Qt6: QMap::unite removed; insert() keeps the same "existing keys win" semantics
     topics.insert(typePlugin->getFunctionTopics());
 
     QMap<std::string, DDSGeneric::TopicDescription>::iterator it = topics.begin();
@@ -72,7 +71,6 @@ public:
       return availDataTopics;
 
     // Convert list of DoTypes, separated by comma (given by user)
-    // Qt6: QStringRef/QString::splitRef removed; QStringView::split provides the same tokenization
     const QString doTypeStr = value(QLatin1String("t"));
     const QList<QStringView> strList = QStringView{doTypeStr}.split(QLatin1Char(','), Qt::SkipEmptyParts);