fix: Remove Boot requirement from workspace to avoid audit error

- Remove Boot=yes from workspace.nspawn configuration
- Use machinectl shell directly without starting/booting container
- Avoids "Failed to reset audit login UID" error in nested containers
- machinectl shell works with non-booted containers via namespace entry

cfg/setup-user.sh

@@ -35,7 +35,6 @@ echo "Creating workspace container configuration..."
 mkdir -p $ROOTFS/etc/systemd/nspawn
 cat > $ROOTFS/etc/systemd/nspawn/workspace.nspawn <<'EOF'
 [Exec]
-Boot=yes
 ResolvConf=copy-host
 
 [Files]
@@ -76,8 +75,6 @@ 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
-        sudo machinectl start workspace 2>/dev/null || true
-        sleep 1
         exec sudo machinectl shell workspace
     else
         # Running as root inside workspace container - start claude