The external-agent-smoke workflow ran `pip install -e .`, which only
installs runtime dependencies. pytest and pytest-timeout live in the
`dev` optional-dependency group in pyproject.toml, so the test step
failed immediately with `No module named pytest` on all three platforms
before running a single test.
Fix: `pip install -e ".[dev]"`
This bug went undetected because every previous PR triggered the workflow
in `action_required` state (fork PRs need maintainer approval to run);
the job never actually executed until now.
CatJuly