empty dashboard matches snapshot at 1280×800

Pin the visible shell that every other browser e2e implicitly relies on: the landing page renders the hydrated workspace-create form at 1366×900 with animations disabled, and the freshly-seeded dashboard renders at 1280×800 with the toolbar position, add-job CTA, and empty-state layout intact. Snapshots are masked for workspace id and the now-timestamp and committed to __snapshots__/.