- Splash Skip button now dispatches `AuthGuestLoginSubmitted` instead of
direct routing, keeping guest auth under the state machine
- Update PWA install dialog copy ("Add to Home Screen") and drop favicon
entry from manifest icons
- Add debug logging and routing sequence docs to splash-button
Configure Progressive Web App capabilities for production builds, enabling offline support and installability. PWA is disabled in dev to avoid HMR conflicts, and switches the build to webpack since PWA tooling requires it.