Possible improvements to GitHub Actions (CI)

logs can't be read without signing in (probably hardcoded site-wide)

something better than installing .NET SDK in Ubuntu

• https://devblogs.microsoft.com/dotnet/dotnet-loves-github-actions/
• https://nixos.org/guides/continuous-integration-github-actions.html
• https://github.com/Elskom/build-dotnet/

misc.

• https://github.com/neysofu/awesome-github-actions-runners#list-of-providers
• #3944
• SAST workflow (https://gitlab.com/YoshiRulz/yoshis-hawk-thoughts/-/issues/97)

T_T migrate from GitLab

• https://docs.github.com/en/actions/migrating-to-github-actions/automated-migrations/migrating-from-gitlab-with-github-actions-importer
• https://docs.github.com/en/actions/migrating-to-github-actions/manually-migrating-to-github-actions/migrating-from-gitlab-cicd-to-github-actions
• need to tweak how artifacts are created, at least for releases: #4126
• TIL GitHub only keeps logs for 90 days!? You can decrease it, but 90 is the max. for public repos. This is useless. GitLab CI keeps all logs until a pipeline is deleted, which is done automatically after a year (at most, configurable).

see also #3013, #3426

Review the repository's GitHub Actions workflows and the linked issues #3944, #4126, #3013, and #3426 before selecting a focused improvement. Compare the concerns about log access, .NET SDK setup, SAST, migration from GitLab, and release artifacts, then confirm the intended scope and acceptance criteria with maintainers.