feat: add DE selector via netinstall groups, move Plasma to livefs

- netinstall.yaml: add 'Desktop' group with 8 DEs as subgroups
  (Plasma default-selected, Xfce, Cinnamon, MATE, LXQt, i3,
   Sway, Hyprland) — users pick their DE during online install
- profile.yaml: move KDE Plasma (plasma group + apps) from
  rootfs/packages to livefs/packages so it's only installed
  when user selects it in netinstall; rootfs now has only
  DE-neutral packages (firefox, calamares, libs, etc.)

iso-profiles/antergos/profile.yaml

@@ -20,72 +20,8 @@ live-session:
     - wireplumber
 rootfs:
   packages:
-    - bluedevil
-    - breeze
-    - breeze-gtk
-    - kactivitymanagerd
-    - kde-cli-tools
-    - kdecoration
-    - kde-gtk-config
-    - kdeplasma-addons
-    - kgamma
-    - kglobalacceld
-    - kinfocenter
-    - kmenuedit
-    - kpipewire
-    - kscreen
-    - kscreenlocker
-    - ksshaskpass
-    - ksystemstats
-    - kwallet-pam
-    - kwayland
-    - kwayland-integration
-    - kwin
-    - kwrited
-    - layer-shell-qt
-    - libkscreen
-    - libksysguard
-    - libplasma
-    - milou
-    - ocean-sound-theme
-    - oxygen
-    - oxygen-sounds
-    - plasma5support
-    - plasma-activities
-    - plasma-activities-stats
-    - plasma-browser-integration
-    - plasma-desktop
-    - plasma-disks
-    - plasma-integration
-    - plasma-nm
-    - plasma-pa
-    - plasma-systemmonitor
-    - plasma-welcome
-    - plasma-workspace
-    - plasma-workspace-wallpapers
-    - polkit-kde-agent
-    - powerdevil
-    - print-manager
-    - qqc2-breeze-style
-    - sddm-kcm
-    - systemsettings
-    - wacomtablet
     - qt6-multimedia-ffmpeg
-    - ark
-    - dolphin
-    - ffmpegthumbs
     - firefox
-    - gwenview
-    - kate
-    - keditbookmarks
-    - kfind
-    - kgpg
-    - kio-admin
-    - konsole
-    - konversation
-    - kwalletmanager
-    - okular
-    - partitionmanager
     - vlc
     - mpv
     - calamares
@@ -139,6 +75,21 @@ livefs:
     - broadcom-wl
     - antergos-live-openrc
     - antergos-grub-theme
+    - plasma
+    - ark
+    - dolphin
+    - ffmpegthumbs
+    - gwenview
+    - kate
+    - keditbookmarks
+    - kfind
+    - kgpg
+    - kio-admin
+    - konsole
+    - konversation
+    - kwalletmanager
+    - okular
+    - partitionmanager
   packages-init:
     dinit:
       - artix-live-dinit