Configure dark theme for Flatpak apps via XDG portals
- Add xdg-desktop-portal-hyprland and xdg-desktop-portal-gtk to packages
- Configure portal to use both Hyprland and GTK backends
- Set GTK dark theme preferences via settings.ini files
- Add XDG environment variables to Hyprland config
- Update CLAUDE.md: add sudo delegation rule, fix distro to Arch Linux
- Include Zenburn-themed ly display manager config
Fixes Flatpak apps (like Tutanota) respecting system dark theme.
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Co-Authored-By: Claude <noreply@anthropic.com>