feat(wishlist): full wishlist feature (heart toggle, navbar counter, wishlist page)

[Asmi768]

Summary

Adds a complete Wishlist system to STYLÉKA:

• Heart toggle on product cards (localStorage-backed)
• Navbar wishlist counter
• New wishlist.html page (remove / move to cart / clear)

Implementation

• Data attributes on product cards (id, name, price, img, url)
• Shared wishlist utils in script.js
• Wishlist page renders saved items; safe fallbacks if cart API not present

Why

Improves UX by letting users save items without adding to cart. Common e-commerce feature, low risk, high value.

Testing

• Toggled wishlist on multiple products
• Verified persistence across reloads
• Removed items and moved items to cart (with fallback)

GSSOC ' 25 Contributor