refactor: Use systemd-nspawn directly instead of machinectl

- Replace machinectl shell with systemd-nspawn -q -D
- Add systemd-nspawn to sudoers permissions
- Simpler and more direct container entry
- No dependency on systemd-machined service

build.zsh

@@ -65,7 +65,7 @@ cp -rf ./cfg/os-release root.x86_64/etc/os-release
 
 # Configure sudoers for wheel group
 echo "Configuring sudoers..."
-arch-chroot root.x86_64 /bin/sh -c 'echo "%wheel ALL=(ALL:ALL) NOPASSWD: /usr/bin/pacman, /usr/bin/pacstrap, /usr/bin/arch-chroot, /usr/bin/rm, /usr/bin/mkdir, /usr/bin/mv, /usr/bin/cp, /usr/bin/poweroff, /usr/bin/reboot, /usr/bin/machinectl, /bin/bash" >> /etc/sudoers'
+arch-chroot root.x86_64 /bin/sh -c 'echo "%wheel ALL=(ALL:ALL) NOPASSWD: /usr/bin/pacman, /usr/bin/pacstrap, /usr/bin/arch-chroot, /usr/bin/rm, /usr/bin/mkdir, /usr/bin/mv, /usr/bin/cp, /usr/bin/poweroff, /usr/bin/reboot, /usr/bin/machinectl, /usr/bin/systemd-nspawn, /bin/bash" >> /etc/sudoers'
 
 # Install aigpt (aios core package)
 echo "Installing aigpt..."

cfg/setup-user.sh

@@ -75,7 +75,7 @@ if [[ -o login ]] && [[ -o interactive ]]; then
     if [[ -z "$INSIDE_WORKSPACE" ]]; then
         # Running as ai user on aios OS - enter workspace container
         export INSIDE_WORKSPACE=1
-        exec sudo machinectl shell workspace
+        exec sudo systemd-nspawn -q -D /var/lib/machines/workspace /bin/zsh
     else
         # Running as root inside workspace container - start claude
         if command -v claude &>/dev/null; then