Review Cairo Gateway contract

[onahprosper]

User Story
As a technical lead, I need to review the Cairo Gateway contract being developed by the Stacknet team, so that we can ensure it meets our requirements, follows best practices, and is ready for deployment on Starknet.

Acceptance Criteria

1. GIVEN the Cairo Gateway contract implementation from Stacknet team
   WHEN reviewing the contract code
   THEN it should implement all required Gateway functionality (create order, settle, refund)

2. GIVEN the Cairo contract review
   WHEN checking for security and best practices
   THEN the contract should follow Cairo/Starknet security guidelines and conventions

3. GIVEN the reviewed contract
   WHEN comparing with existing Solidity Gateway
   THEN feature parity should be maintained with any necessary adaptations for Cairo/Starknet

Tech Details

• Review Cairo contract implementation for:

  • Order creation and management
  • Settlement functionality
  • Refund mechanism
  • Fee-split implementation
  • Access control and permissions
  • Event emissions
  • Storage patterns
  • Gas optimization

• Ensure compatibility with:

  • Starknet architecture
  • Cairo language best practices
  • Our existing backend integration patterns
  • Indexer requirements for event tracking

• Verify testing coverage and documentation

• Check upgradeability pattern if applicable

Notes/Assumptions

• Stacknet team is handling the Cairo implementation
• Contract should maintain functional parity with EVM Gateway
• Cairo/Starknet may require different architectural patterns than Solidity
• Integration with aggregator backend may need adjustments for Starknet
• Review should cover both functionality and security aspects