feat: 马丽 navigates essential functionality without delay

[toshify]

马丽 sees the loading screen until the essential functionality has been loaded, so that when she starts navigating the app, she is NOT interrupted by loading screens.

Requires

• Configures assets to load
  • before displaying loading screen
    • one page with loading spinner/animation
  • during animation
    • instructions introduction page
    • audio for instructions
    • start screen assets
    • start screen instructions assets
    • global menu assets
  • lazy/on demand later
    • Lesson assets
    • Lesson instructions