Sub-ticket of VENUS-78 PWA mobile install-prompt: when app opened on a phone without it installed, offer add-to-home. Android: capture beforeinstallprompt -> dismissible custom install button/banner (Spanish). iOS Safari: manual 'Compartir -> Agregar a inicio' instructions banner (iOS cannot auto-prompt). Mobile-only, hidden when already installed (display-mode:standalone) or dismissed. Builds on VENUS-77 manifest/SW. · venus