stimcirq requirement introduces circular dependency

[pavoljuhas]

Describe the issue

As of #7101 we have stimcirq in dev-tools as a dependency for development environment. stimcirq requires cirq-core so the environment ends up with 2 copies of cirq-core - one in devenv/site-packages and another in PYTHONPATH from repo sources. This may cause confusion if PYTHONPATH is not set or if python is run in an isolated mode.

Proposed solution

Update cirq-all-nocontrib so it installs cirq in an editable mode. That way stimcirq would accept local cirq as its requirement rather than installing cirq-core on its own.

Also look into updating no-contrib.env.txt so it does not install contrib dependencies via notebook.txt.

Tell us the version of Cirq where this happens

1.7.0.dev at 149e266

[mhucka]

Discussed during Cirq Cynq 2026-02-18:

• This is not an issue for end users, but it is a potential complication for developers.