Add live search, functional product buttons, and light/dark theme switcher

[Dhanya234]

What was changed:

• Search bar now shows live results as you type
• Eye button opens a product quick-view modal
• Add to Cart and Wishlist buttons now work and update the header counts
• Added light/dark mode toggle in the header
• Added 5 accent color options in the theme panel
• Theme preference is saved and remembered on page refresh

How to test:

1. Type in the search bar and see results appear
2. Click the eye icon on any product card
3. Click Add to Cart and see the cart count update
4. Click the moon icon to switch to dark mode
5. Open the palette panel and try different colors
6. Refresh the page and confirm your settings are saved