Motivation

• Ensure changes to PYWRAP_PIP_ARGS or PYWRAP_LOCAL_FIRST trigger dependency reinstalls by including them in the venv marker check.
• Provide a local-first installation mode that downloads packages before installing to support offline or cached installs.
• Persist installation options in the venv marker so environment creation is reproducible and inspectable.

Description

• Include pip_args and local_first in the marker validation so marker mismatches will trigger reinstall when these settings change.
• Extend _install_deps to accept a local_first flag and implement a _pip_install helper that uses pip download into a temporary directory and then pip install --no-index --find-links when local_first is enabled, with cleanup of the temp dir.
• Write pip_args and local_first into the .venv/.pywrap/ok.json marker when creating/updating the marker.
• Document PYWRAP_LOCAL_FIRST in README.md and add the unit test test_local_first_records_marker_flag in tests/test_wrapper.py.

Testing

• Ran the unit test suite with python -m unittest tests/test_wrapper.py.
• The test run reported Ran 9 tests and exited OK.
• The new test test_local_first_records_marker_flag passed as part of the suite.

Codex Task