v0.4.0

Added

• GitHub ships as a package. The GitHub Actions runtime now ship as Ritten.GitHub.
• Git and .NET ship as packages. Ritten.Git and Ritten.DotNet carry their own tech-specific stuff.
• The engine runs external commands. The Ritten.Commands module moved from the CLI into Ritten.Core.
• Steps can read the pull request under review. The engine owns a PullRequest contract (number, base ref) and an IPullRequestLabels read returning Label values (name, color, description), and the active runtime supplies them — GitHub Actions fills both from its own claims and the GitHub API. Where nothing can answer — a local run, a runtime without the concept — labels read as null, distinct from a pull request that simply carries none, and a host can always register its own implementation to take precedence.

Changed

• IBuildReport is now IWorkflowReport. It more accurately reflects that the report covers one workflow execution.
• Run context is injected directly. RunContext (and the new PullRequest) are immutable records that steps and services take by type, no longer configured or consumed through IOptions.
• Exit codes are value objects. ExitCode replaces the bare int (and the WorkflowExitCodes constants, which now live on it as ExitCode.Success and friends). It converts implicitly to and from int at the process boundaries.
• Result sinks are called on start and finish. IWorkflowResultSink (was IReportSink) can announce the run when it starts with a pending pull request comment, and publishes a single artifact.
• MarkdownReportRenderer is public. And now takes the Report whole, for any sinks that want to render in Markdown.