Remove i3 desktop profile and st terminal

Elimina completamente la sessione desktop i3 (X11), ormai non più usata
(gli host espongono solo sway e Hyprland su Wayland):
- ruolo profile_desktop_i3 e voce emptty i3.desktop
- desktop_i3_packages e i guard 'i3' in desktop_sessions_enabled
- desktop_i3_dotfiles e host_i3_dotfiles (autorandr X11)
- dotfiles i3/X11: .xinitrc, i3, i3blocks, picom, polybar, autorandr
- task host-specifici i3 (copy dotfiles, wrap prime-run su nymph)
- rimuove st (terminale X11 da sorgente) da desktop_void_source_tools
- consolida lo script live in scripts/remove_i3.sh, elimina cleanup-i3.sh
- aggiorna la documentazione (README/AGENTS/CLAUDE/knowledge)

Config Emacs lasciata invariata di proposito.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

ansible/inventory/group_vars/void.yml

@@ -3,13 +3,6 @@ void_xbps_repositories:
   - name: hyprland-void
     url: https://raw.githubusercontent.com/sofijacom/hyprland-void/repository-x86_64-glibc
 
-desktop_void_source_tools:
-  - name: st
-    repo: https://codeberg.org/fscotto/st
-    build_cmd: make
-    binary_name: st
-    install_name: st
-
 void_packages_base:
   - 7zip
   - NetworkManager
@@ -133,31 +126,6 @@ desktop_common_packages:
   - xdg-user-dirs
   - xfce-polkit
 
-desktop_i3_packages:
-  - arandr
-  - autorandr
-  - feh
-  - i3
-  - i3blocks
-  - i3blocks-blocklets
-  - i3lock-color
-  - i3status
-  - dunst
-  - picom
-  - polybar
-  - rofi
-  - scrot
-  - setxkbmap
-  - volumeicon
-  - xclip
-  - xfce4-clipman-plugin
-  - xfce4-screenshooter
-  - xkbutils
-  - xorg-fonts
-  - xorg-minimal
-  - xss-lock
-  - xdotool
-
 desktop_sway_packages:
   - cliphist
   - dunst