GNOME resolves the MPRIS media-widget app icon via DesktopEntry -> the installed
<id>.desktop -> Icon=. Rename the Arch desktop file to com.blitzfc.qbz.desktop,
set Icon=com.blitzfc.qbz, and install the hicolor icon as com.blitzfc.qbz.png so
the basename matches the published DesktopEntry. Other channels (AUR/Gentoo/Snap
+ Tauri bundle/release workflow) documented in qbz-nix-docs (release-time,
build-test required). Flatpak was already correct.
cc