Harbor egress-control build context

These notes are for maintainers preparing the optional Docker network-control helper; they are not task instructions.

egress-control/ is an unmodified copy of the five files in the Docker egress-control context of the harbor==0.22.0 Python package. The package metadata declares Apache-2.0; its accompanying license text is preserved in LICENSE.

The CLI normalizes file and directory permissions before calculating Harbor's docker_build_context_hash with Dockerfile, empty build arguments and platform linux/amd64. The declared hash is recorded in assets/sources.json under harbor-0220-egress-control; the host-support image declaration uses the same value. The consistency test checks both declarations against Harbor's installed context and the normalized vendored files:

python -m pytest src/tcsexam/tests/test_harbor_egress_control.py

Keep provenance material outside egress-control/: Harbor's hash covers every file and its mode in that directory.