Add new icons and screenshots for web app manifest

- Introduced multiple icon files in WEBP format with various sizes (192x192, 196x196, 228x228, 256x256, 384x384, 512x512).
- Added new screenshot files in AVIF format for the web app manifest, including hero and prepare screenshots in both standard and wide formats.
- Updated the manifest.ts file to include the new icons and screenshots, adjusting background and theme colors.

Author: upayanmazumder