The target laptop account has no sudo. install.sh now runs without root once the
system packages exist; if they're missing and the account can't sudo it prints
the exact command and stops. New install-system.sh holds the one-time
"sudo apt install python3-tk python3-venv git" for an admin account.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
