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/host_vars/nymph.yml

@@ -24,14 +24,6 @@ host_packages:
 host_enabled_services:
   - tlp
 
-host_i3_dotfiles:
-  - src: .config/autorandr/
-    dest: .config/autorandr/
-    mode: preserve
-  - src: .config/wireplumber/wireplumber.conf.d/60-camera-priority.conf
-    dest: .config/wireplumber/wireplumber.conf.d/60-camera-priority.conf
-    mode: "0644"
-
 host_sway_dotfiles:
   - src: .config/sway/host.conf
     dest: .config/sway/host.conf