chore(bootsplash): regenerate assets, add generate script, document iOS codegen

- Add scripts/bootsplash-generate.cjs (temp copy avoids Sharp I/O clash)
- Point bootsplash:generate at the script; background #111827
- Refresh iOS/Android splash assets and assets/bootsplash scales
- Document New Architecture Props.h / pod install in development.md

Made-with: Cursor

Author: maximcoding