* Add a macOS 26 layered app icon with dark, clear and tinted variants.
The new pgAdmin4.icon Icon Composer document splits Slonik into body and
line layers over the existing light gradient, using the system dark fill
in dark mode. It is compiled ahead of time into Assets.car, so the build
does not need Xcode 26, and pgAdmin4.icns remains the icon on older
releases.
Closes#10473
* Match the macOS 26 icon's Slonik to the old icon's size and drop its glow.
Remove the thick white silhouette from the body layer, soften the group
shadow, and scale and position Slonik to match pgAdmin4.icns.
* Thin the macOS 26 icon's white lines to match pgAdmin4.icns.
ebe4617c00