Run Buildkite jobs on Tuist Runners

Tuist Runners now take jobs from Buildkite. Connect a cluster under Settings › Integrations with a cluster agent token, create a self-hosted queue named after a runner profile such as tuist-macos, and target it from a step with agents: { queue: tuist-macos }.

Jobs run on the same macOS and Linux fleet as GitHub Actions jobs and show up under Runners with their logs and duration. The guide walks through the setup.