Upgrade Celo and Scroll Gateway contracts for fee-split

[onahprosper]

User Story
As a developer, I need to upgrade the Gateway contracts on Celo and Scroll networks to implement the fee-split functionality, so that the contracts support the new fee distribution mechanism.

Acceptance Criteria

1. GIVEN the upgraded Gateway implementation with fee-split functionality
   WHEN deploying to Celo network
   THEN the proxy should be upgraded successfully and verified on block explorer

2. GIVEN the upgraded Gateway implementation with fee-split functionality
   WHEN deploying to Scroll network
   THEN the proxy should be upgraded successfully and verified on block explorer

3. GIVEN the upgraded contracts on both networks
   WHEN interacting with the contracts
   THEN the fee-split functionality should work as expected

Tech Details

• Upgrade existing Gateway proxy contracts on:

  • Celo (using Celoscan/Sourcify for verification)
  • Scroll (using Scrollscan for verification)

• Use Hardhat Ignition for deployment: `npx hardhat ignition deploy ignition/modules/GatewayImplementation.ts --network `

• Verify upgraded implementation contracts on respective block explorers

• Ensure proxy admin permissions are properly configured

• Test fee-split functionality after upgrade

Notes/Assumptions

• Existing proxy contracts will remain at the same addresses
• Only the implementation contract needs to be deployed and upgraded
• Fee-split functionality is the primary feature being added
• Backward compatibility with existing orders should be maintained