* QDesktopWidget -> QScreen
Simplifications:
* After setting new screen/geometry, forget them and let resizeEvent() handle any updates.
* Specifically, don’t connect to screen size change signals.
* Specifically, setScreen() only sets the new widget position and then waits for resizeEvent().
* This also means applyNewScreenSize() and repositionContent() can be collapsed into resizeEvent().
* Replace recalcGeometry() by setScreen(defaultScreen()), where defaultScreen() only checks the configuration.
David Hurka