Add shallow circuits experiment (#447)

* Add shallow circuits experiment

Builds and runs experiment for finding hidden linear functions (HLF) with shallow circuits.
This module provides the fundamental building blocks for generating, executing,
and analyzing results for finding HLF with shallow circuits experiment,
as described in https://arxiv.org/abs/2512.02284.

Author: shashwatk1998

dev_tools/write-ci-requirements.py

@@ -12,7 +12,7 @@
     'current': '~=1.4.0',
     'next': '>=1.5.0',
 }
-"""Give names to relative Cirq versions so CI can have consistent names while versions 
+"""Give names to relative Cirq versions so CI can have consistent names while versions
 get incremented."""
 
 
@@ -76,7 +76,7 @@ def main(*, out_fn: str = 'ci-requirements.txt', relative_cirq_version: str = 'c
 
     extras_require = [
         'otoc', 'qaoa', 'optimize', 'hfvqe', 'fermi_hubbard', 'qml_lfe',
-        'seniority_zero', 'qcqmc'
+        'seniority_zero', 'qcqmc', 'contextuality'
     ]
     extras_require = {
         r: _parse_requirements(pathlib.Path(REPO_DIR / f'recirq/{r}/extra-requirements.txt'))