feat: add interactive smart contract carousel to pitch deck

- Create SmartContractCarousel.tsx with all 9 smart contract instructions
- Replace static redeem_coupon.rs snippet with interactive carousel
- Add navigation controls (arrows, dots, 9-button grid)
- Include code syntax highlighting and category badges
- Show instruction details: initialize_merchant, create_coupon, claim_coupon,
  purchase_coupon, redeem_coupon, update_coupon_status, list_for_resale,
  purchase_from_resale, transfer_coupon
- Enhance pitch deck technical showcase for judges

Author: rz1989s