Feature/erc4337 implementation

[Aboudjem]

ERC-4337 Account Abstraction Implementation

This PR adds ERC-4337 (Account Abstraction) support to onchain-id Identity contracts with comprehensive testing infrastructure using Foundry.

Changes Made

🔧 Foundry Setup

• Added Foundry configuration (foundry.toml) with optimized compiler settings
• Configured remappings for dependencies (@account-abstraction, @OpenZeppelin, forge-std)
• Updated .gitignore to exclude Foundry artifacts (out/, cache/)

🧪 Test Infrastructure

• UserOpBuilder Library: Helper contract for constructing and signing ERC-4337 UserOperations

• Target Mock Contract: Test contract for validating execution flows

• Comprehensive Test Suites:

  • IdentityAA.t.sol: 11 tests covering validation, nonce management, EntryPoint interaction, and signature verification
  • IdentityAA_Batch.t.sol: 9 tests for batch execution functionality
  • All tests passing (20/20 ✅)

📝 Documentation

• Added IMPLEMENTATION_GUIDE.md with detailed technical overview
• Includes architecture diagrams, security considerations, and integration guides
• Documents key purpose (5) for AA signers and execution bypass patterns

🔄 Contract Updates

• Updated pragma statements in IdentityUtilities contracts for Foundry compatibility
• Modified hardhat.config.ts and package.json to support dual testing framework

Technical Notes

Hardhat v3: Not included in this PR due to significant breaking changes. Recommend handling the Hardhat v3 upgrade in a separate branch to avoid complicating the ERC-4337 implementation review.

Testing Framework: Currently using Foundry for ERC-4337 tests. Foundry provides better tooling for testing Account Abstraction patterns (UserOperation simulation, EntryPoint integration, gas reporting).

Next Steps

• Review and merge ERC-4337 implementation
• Address Hardhat v3 upgrade in separate PR
• Consider adding additional edge case tests