Add back-to-top button with golgappa icon to all pages

[Tejashwini200532]

Fixes #64

Description

Added a "Back to Top" button with a golgappa icon to all pages for improved user experience and navigation.

Pages Updated

• ✅ Home (index.html)
• ✅ Menu (menu.html)
• ✅ Cart (cart.html)
• ✅ Favorites (favorites.html)
• ✅ Orders (orders.html)
• ✅ Recommendations (recommendations.html)

Changes Made

1. Added back-to-top button HTML to all pages
2. Added CSS styling for the button (.back-to-top-container, #backToTop, .back-to-top-text)
3. Created initBackToTopButton() function in js/main.js
4. Integrated function into init() for proper DOM readiness
5. Merged latest changes from main branch

Technical Details

• Button appears when user scrolls > 200px down
• Smooth scroll animation to top
• Fixed position with z-index: 9999
• Hover effect with transform animation
• Golgappa icon (img/golgappa.png)

Testing

• Button appears/disappears on scroll correctly
• Click handler works on all pages
• No console errors
• Works across all screen sizes