uv

9b8d6989 - Allow pinning managed Python versions to specific build versions (#15314)

Allow pinning managed Python versions to specific build versions (#15314) Allows pinning the Python build version via environment variables, e.g., `UV_PYTHON_CPYTHON_BUILD=...`. Each variable is implementation specific, because they use different versioning schemes. Updates the Python download metadata to include a `build` string, so we can filter downloads by the pin. Writes the build version to a file in the managed install, e.g., `cpython-3.10.18-macos-aarch64-none/BUILD`, so we can filter installed versions by the pin. Some important follow-up here: - Include the build version in not found errors (when pinned) - Automatically use a remote list of Python downloads to satisfy build versions not present in the latest embedded download metadata Some less important follow-ups to consider: - Allow using ranges for build version pins