GitHub announced the deprecation of the `macos-13` runner image[^1],
which will be completely removed by December 4th, 2025.
This commit migrates all workflows to use `macos-15-intel` runners
following the announcement's recommendation.
This also uses `ubuntu-latest` alias instead of explicit `ubuntu-24.04`.
[^1]: https://github.blog/changelog/2025-09-19-github-actions-macos-13-runner-image-is-closing-down/
Signed-off-by: Aofei Sheng <aofei@aofeisheng.com>
