Function format_github_actions 

pub fn format_github_actions(secrets: &HashMap<String, String>) -> String

GitHub Actions format: ::add-mask::VALUE workflow command followed by KEY=VALUE for each secret, sorted by key.

Append to $GITHUB_ENV in a run: step:

- run: tsafe export --format github-actions >> $GITHUB_ENV

The runner processes ::add-mask:: lines to mask values in log output, and KEY=VALUE lines are loaded into subsequent steps automatically.