Release v7.27.3

Added

• The corpus verification job replays the screens authoring workflow on the pinned public vector: it installs the pinned cratis CLI, materializes the published Cratis.Screenplay.CanonicalCorpus folder source (the corpus stays Screenplay-owned and is not copied), replays the stdio MCP transcript with the revision-checked column edit, renders the edited folder and requires the column in the generated scene.json. It runs locally with screens-smoke.sh <work-folder>; the pins live in screens-smoke.json. The browser step still needs Docker and Chromium and stays a documented manual step. (part of #536)