[Completer] Minimum size popup, fall back to compact design if not possible. (#7111)

* [Completer] Minimum size popup, fall back to compact design if not possible.

Took 15 minutes

Took 6 seconds


Took 5 minutes

* [Completer] Fix popup going offscreen by clamping in screen coordinates

The position clamping in applyPopupWidth() was comparing popup->pos()
(parent coordinates) against screen->availableGeometry() (screen
coordinates).  When the parent widget is not at the screen origin the
clamping computed a position in the wrong coordinate space, placing the
popup offscreen.  Convert to global coordinates first, clamp, then map
back to parent coordinates.

* [Completer] Clamp popup from geometry() in screen coordinates

setMinimumWidth() already widens the popup synchronously, so the old
width() < minWidth guard never ran and the popup grew past the right
screen edge. The popup is also a top-level Qt::Popup window, so move()
takes global coordinates and the mapFromGlobal round-trip moved it to
the top-left of the screen. Clamp x from geometry() after
setMinimumWidth() and move(QPoint(clampedX, popup->y())) directly.

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Co-authored-by: Lukas Brübach <Bruebach.Lukas@bdosecurity.de>

cockatrice/src/interface/widgets/utility/card_completer_styler.h

@@ -52,6 +52,7 @@ private:
     void stopPreviewFade();
     void reposition();
 
+    void applyPopupWidth();
     void updateOrientation();
     void ensureClosestSelected();