chore: attempt to speed up tests

Author: parthea

.github/workflows/unittest.yml

@@ -50,7 +50,7 @@ jobs:
         PY_VERSION: ${{ matrix.python }}
         # Use UV to speed up testing
         # Force standard venv backend for 3.15, leave empty to let nox-uv handle others
-        NOX_VENV_BACKEND: ${{ matrix.python == '3.15' && 'venv' || '' }}
+        NOX_FORCE_VENV_BACKEND: ${{ matrix.python == '3.15' && 'venv' || '' }}
         # Unset the global uv seeder for 3.15 so the standard venv backend doesn't try to use virtualenv internals
         VIRTUALENV_SEEDER: ${{ matrix.python == '3.15' && '' || 'uv' }}
         # Workaround: Allows libcst to compile on Python 3.15+ while PyO3 catches up