CI / CI (push) Failing after 4s
The self-hosted astral-uv runner is in China; pulling build deps from pypi.org is slow and often times out. Set UV_DEFAULT_INDEX on the 'Build package' step so uv's build-environment resolution goes through the Tsinghua mirror. This complements the [tool.uv.index] url=... block in pyproject.toml — env wins over the file config when both are present, so the mirror is used consistently. Co-Authored-By: Claude <noreply@anthropic.com>