feat: Set up Hardhat development environment for contracts

[rafamiziara]

Description

Set up the Hardhat development environment in the packages/contracts/ directory to support smart contract development, testing, and deployment.

Acceptance Criteria

• Initialize Hardhat project structure
• Configure Hardhat for TypeScript
• Set up network configurations for Polygon Amoy testnet
• Add essential plugins (gas-reporter, coverage, etherscan verification)
• Create basic folder structure (contracts/, scripts/, test/)
• Add environment variables configuration
• Create sample deployment and test scripts

Technical Requirements

• Use latest Hardhat version
• Configure for Solidity ^0.8.20
• Include OpenZeppelin contracts for upgradeable patterns
• Set up proper TypeScript configuration
• Configure deployment to Polygon Amoy testnet

Definition of Done

• Hardhat environment is fully configured and functional
• Can compile, test, and deploy contracts to Amoy
• Proper TypeScript support and linting
• Documentation for local development setup