Fix README: styles are JSON tokens, not SCSS

Co-authored-by: johndoe6345789 <224850594+johndoe6345789@users.noreply.github.com>

README.md

@@ -227,7 +227,7 @@ packages/{packageId}/
 ├── components/
 │   └── ui.json           # Declarative JSON components
 ├── styles/
-│   └── styles.scss       # Optional styles
+│   └── tokens.json       # Design tokens (colors, spacing, shadows, etc.)
 └── static/
     └── assets/           # Images, fonts, etc.
 ```