Add NFT Factory Implementation with ERC721 Support

[codebestia]

PR Description

This PR introduces a complete NFT factory implementation with full ERC721 functionality, including minting, burning, and transfer capabilities.

✍️ Changes Made

src/Nft.cairo - New NFT Factory Contract

• Added: Complete NftFactory contract implementation using OpenZeppelin components
• Features:
  • ERC721 standard compliance with SRC5 metadata support
  • Minting functionality for creating new NFTs
  • Burning functionality with owner-only access control
  • Full ERC721 transfer and approval mechanisms
  • Configurable name, symbol, and base URI
• Security: Owner-based access control for minting and burning operations

src/interfaces/ierc721.cairo - ERC721 Interface Definitions

• Added: Complete ERC721 interface definitions
• Interfaces:
  • IERC721: Core ERC721 functionality (transfer, approve, balance_of, etc.)
  • IERC721Metadata: Metadata functions (name, symbol, token_uri)
  • IERC721Mintable: Minting and burning capabilities
• Standards: Implements ERC721 standard with additional mintable functionality

tests/test_nft_factory.cairo - Comprehensive Test Suite

• Added: Complete test coverage for NFT factory functionality
• Test Cases:
  • ✅ Basic contract deployment and metadata verification
  • ✅ NFT minting with proper ownership assignment
  • ✅ NFT burning with owner validation
  • ✅ Transfer functionality between addresses
  • ✅ Approval system for third-party transfers
  • ✅ Error handling for unauthorized operations
• Coverage: Tests both happy path and edge cases with proper access control validation

🚀 Benefits

1. Standards Compliance: Full ERC721 standard implementation
2. Extensibility: Modular design using OpenZeppelin components
3. Security: Robust access control and validation
4. Testability: Complete test coverage for all functionality
5. Integration Ready: Interfaces designed for easy integration with marketplace

🧑🏾‍💻 Testing

All tests covering:

• Contract deployment and initialization
• NFT minting and burning operations
• Transfer and approval mechanisms
• Error handling for unauthorized access
• Metadata functionality

Related Issue

Closes #33