On a hard reload the root route briefly showed a generic centered pulse
(PageSkeleton) while the layout chunk downloaded, then snapped to the
topbar skeleton. Point the root Fallback at MainLayoutSkeleton so the
chunk-load fallback matches the loader's own skeleton and the transition
is seamless. PageSkeleton is now unused and removed.
Signed-off-by: Émile Ré <emile@probo.com>
6ec7efb4fc