components/PageSkeleton.jsx already owned `.sk-page` for its loading
archetypes, including `gap: $space-4`. The new shell reused the name, so every
page built on PageLayout inherited a 16px flex gap between the top bar and the
content — invisible on padded pages, but on Terminal/Logs it showed as a band
of page background under the bar, which is exactly the "weird space" reported.
The shell is `.sk-pageshell` now; the skeleton keeps `.sk-page`. The smoke test
gained a vgap assertion (content top must equal the bar's bottom edge), which
is what would have caught this in the first place.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
