terminalstripdrawer.cpp: fix two Qt6 compile errors

- Add missing <QHash> include: QHash<QUuid, QVector<QPointF>> was
  only forward-declared transitively under Qt5's heavier headers;
  Qt6's leaner <QPainter> etc. no longer pull it in.

- Replace QPolygonF{points_} with QPolygonF(points_): under Qt6,
  QPolygonF inherits QList<QPointF>'s constructors via 'using
  QList<QPointF>::QList;', including the std::initializer_list<T>
  one. Brace-init-list construction with a single argument first
  considers only initializer-list constructors before falling
  back to regular ones, which trips up overload resolution here
  even though points_ is exactly a QList<QPointF> (QVector is a
  plain alias for QList under Qt6). Plain parenthesised
  construction sidesteps that resolution phase entirely and binds
  directly to QPolygonF(const QList<QPointF>&).

sources/TerminalStrip/GraphicsItem/terminalstripdrawer.cpp

@@ -18,6 +18,7 @@
 #include "terminalstripdrawer.h"
 
 #include <QPainter>
+#include <QHash>
 
 namespace TerminalStripDrawer {
 
@@ -271,7 +272,7 @@ void TerminalStripDrawer::paint(QPainter *painter)
 			auto pen_{painter->pen()};
 			pen_.setWidth(2);
 			painter->setPen(pen_);
-			painter->drawPolyline(QPolygonF{points_});
+			painter->drawPolyline(QPolygonF(points_));
 			painter->restore();
 		}
 	}