test: harden scheduling review boundaries

tests/scheduling/test_lock_identity.py

@@ -123,6 +123,7 @@ def test_competing_processes_share_the_canonical_lock(tmp_path: Path) -> None:
         )
         proc = subprocess.run(
             [sys.executable, str(script_path)],
+            cwd=Path(__file__).resolve().parents[2],
             capture_output=True,
             text=True,
             timeout=60,