Fixes#37748.
Sort skill package archive entries by relative POSIX archive name so generated `.skill` bundles are reproducible regardless of filesystem traversal order.
Verification:
- `PYTHONDONTWRITEBYTECODE=1 python3 skills/skill-creator/scripts/test_package_skill.py`
- `git diff --check origin/main...HEAD`
- GitHub CI run 26690938925 on `43a0fdf7175f33a5c74bc7ff92723ebf5efc4df9`: all checks passed except repeated unrelated no-output timeouts in `checks-node-agentic-commands-doctor` and `checks-node-core-runtime-infra-state` after visible tests passed.
878e433d81