index.html carries the overlay markup and styles inline so it paints before
any script; public/splash.js (external, for the CSP) plays the logo
animation from icons/ultimo-splash.html, holds, fades out after ~3.25 s and
removes itself. Skipped at phone sizes (same query as useIsMobile) and in
pop-out compose windows; a click skips it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
