Fixes: #591

Add earn hook for stCELO

Overview

This PR adds support for stCELO (https://app.stcelo.xyz/) in Valora's Earn feature through the hooks platform. While stCELO is already supported as an ERC20 token, this implementation enables it as an earn opportunity with deposit and withdraw capabilities.

Implementation Details

• Added stCELO hook in src/apps/stcelo/ with the following components:
  • positions.ts: Core hook implementation that provides:
    • Position definitions for both mainnet and Alfajores testnet
    • Exchange rate and TVL information
    • Detailed display properties including risks and safety levels
    • 3-day unstaking period warning
  • shortcuts.ts: Implements deposit and withdraw shortcuts
  • abis/stcelo.ts: Contract ABI definitions for required functions
  • positions.test.ts: Comprehensive unit tests

Key Features

1. Liquid Staking: Users can stake CELO while maintaining liquidity through stCELO
2. Yield Tracking: Displays variable staking APY from Celo epoch rewards
3. Safety Information:
   • Non-custodial protocol
   • No principal slashing risk
   • 3-day withdrawal period (liquidity risk)
4. User Actions:
   • Deposit (stake) CELO
   • Withdraw (unstake) stCELO
   • View current exchange rate and TVL

Testing

• Unit tests cover:
  • Position definitions for both networks
  • Error handling for unsupported networks
  • Contract interactions (exchange rate, total assets)
  • Token information validation

Notes

• The stCELO contract doesn't implement the symbol() function, but this is handled gracefully in the hook implementation
• APY is reflected through the increasing stCELO:CELO exchange rate rather than explicit rewards