Polish: Add proper favicon and site icons

[Mosas2000]

Summary

The application references /icon.png in the wallet connect configuration, but there is no evidence of favicon or site icons being properly configured.

Recommended Files

1. /public/favicon.ico (16x16 and 32x32)
2. /public/icon-192.png (for PWA)
3. /public/icon-512.png (for PWA)
4. /public/apple-touch-icon.png (for iOS)
5. /public/og-image.png (for social sharing)
6. manifest.json (for PWA support)

Impact

Low - Professional polish that makes the application feel complete.