[Icons] Migrate UI glyphs to palette-token SVGs (#7595)

* [Icons] Migrate UI glyphs to palette-token SVGs

Runtime inversion is not a theming system: it rotates hue, breaks duotone art
and mishandles alpha, and a QPixmap snapshot cannot follow a palette change.
Redraw the top-level UI glyph set on a 24x24 grid with `currentColor` as the
paint token, drop Inkscape/Sodipodi cruft, and delete the icons whose metaphor
was duplicated (cogwheel/gear -> settings, scale_balanced -> scales,
update.png -> reload).

Load the glyphs through `loadThemedIcon` so the engine resolves the token from
the palette on every request, and let `themePixmap` use the same resolution for
one-shot pixmaps. `loadColorAdjustedPixmap` is gone; every caller now keeps a
QIcon, which `SettingsButtonWidget::setButtonIcon` accepts instead of a QPixmap.

Content art (mana, counters, countries) keeps its authored colors.

Add a render test covering aspect ratio, palette flips, icon modes and
high-DPI pixmaps.

* [Tests] Keep the icon render test QApplication alive until exit

Creating it as a function-local static tears it down before Qt's library statics
at exit, and libQt6Network then runs QObject destructors against freed memory —
a SEGV the sanitizer leg reports after the tests have already passed. Leak the
application instead, the usual pattern for a test binary.

* [Icons] Render lock and dropdown glyphs through the icon engine

Both generators rendered the sentinel SVG to a fixed height x height pixmap
at DPR 1. The pre-migration path rendered larger and let QIcon scale it, so
on a 2x display the games-list lock (13px) and the banner dropdown arrow
(24px) came back crisp; the new path hands the widget a DPR-1 bitmap that
gets upscaled and blurred.

- The games list asks the themed engine for `icons/lock` directly, so the
  item view paints it at the device pixel ratio and the lock also follows
  HighlightedText on a selected row.
- The dropdown goes through `loadThemedIcon(...).pixmap(size, dpr)`, which
  keeps the glyph's aspect ratio and renders at the requested ratio.
- LockPixmapGenerator has no consumer left, so it and its cache are gone.

---------

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

cockatrice/src/interface/widgets/tabs/tab_public_decks.cpp

@@ -2,6 +2,7 @@
 
 #include "../../../client/settings/cache_settings.h"
 #include "../../deck_loader/deck_loader.h"
+#include "../../theme_icon.h"
 #include "../cards/card_size_widget.h"
 #include "../general/layout_containers/flow_widget.h"
 #include "../interface/theme_manager.h"
@@ -63,8 +64,8 @@ TabPublicDecks::TabPublicDecks(TabSupervisor *_tabSupervisor, AbstractClient *_c
     headerLayout->addStretch(1);
 
     // Filter/toolbar row, matching the Visual Deck Storage: color identity filter
-    // first, the search bar stretching in the middle, and the quick settings
-    // cogwheel at the end. The card size slider lives inside the cogwheel popup.
+    // first, the search bar stretching in the middle, and the quick-settings button
+    // at the end. The card size slider lives inside its popup.
     emptyLabel = new QLabel(tr("This user has not published any decks."), this);
     emptyLabel->setAlignment(Qt::AlignCenter);
     emptyLabel->setVisible(false);
@@ -79,7 +80,7 @@ TabPublicDecks::TabPublicDecks(TabSupervisor *_tabSupervisor, AbstractClient *_c
     colorIdentityFilter = new DeckPreviewColorIdentityFilterWidget(this);
     searchWidget = new VisualDeckStorageSearchWidget(this);
     refreshButton = new QToolButton(this);
-    refreshButton->setIcon(QPixmap("theme:icons/reload"));
+    refreshButton->setIcon(loadThemedIcon(QStringLiteral("icons/reload")));
     refreshButton->setFixedSize(32, 32);
     quickSettingsWidget = new VisualDeckStorageQuickSettingsWidget(this);
     quickSettingsWidget->setPublicDecksMode(true);