uv venv does not bundle pip by default (unlike python3 -m venv), so when the
venv python was on PATH, ensure_installed_host's 'python3 -m pip install' failed
with 'No module named pip'. Apply --seed across the 4 copies of the venv-setup
block (install.sh, install-nightly.sh, run.sh, run-docker.sh).
dguiducci