fix: install.sh --check/--write-project-discovery rejects repo names (argparse ordering) #565

Overview

On main, tests/test_skill_install.py fails 10–11 tests with project_discovery.py: error: unrecognized arguments: <repo>. bin/install.sh calls project_discovery.py check --root "$PYAUTO_ROOT" "$@". Because the repo names come after --root, plain parse_args() has already given the repos positional (nargs='*') an empty list, and then rejects the trailing names.

Plan

• Parse with parse_intermixed_args(), which accepts the names in any position.
• Witness: pytest tests/test_skill_install.py goes from 10 failed to 22 passed.

Original Prompt

Mind: active/project_discovery_argparse_ordering.md (filed 2026-11-03 at the human's request, from the PR #564 test run).