fix: resolve menu rendering, syntax errors, and duplicate UI bugs

[PARNITA-SINGH]

What was fixed

• Added missing <script src="js/recommendations.js"> to menu.html
• Fixed duplicate removedItem declaration in removeFromCart()
• Removed require() statements incompatible with browser environment
• Removed export keyword from functions loaded as plain scripts
• Fixed stray ); causing SyntaxError in event listener
• Removed orphaned newFeatures and main text artifacts from merge
• Removed duplicate Add button and broken ₹undefined / NaN% OFF UI
• Removed cartManager.validate() call for undefined method

Before & After
Menu items now render correctly with clean price display and single Add button.

BEFORE

AFTER

[PARNITA-SINGH]

Hi @PatelHarsh2006 , Just following up on this PR — I'd love to get some feedback. This was submitted as part of GSSoC'26 and also add the label of GSSOC to my PR. Please let me know if any changes are needed! 🙂