Replace the once-per-session sessionStorage guard (which suppressed the loading
screen after its first appearance) with entry-aware logic: show on app entry
and reloads, suppress on internal link navigations and back/forward.
InjectBootSplash middleware shows a self-branded loading splash once per session
while the app boots, then fades out.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>