feat: ERC-7579 Modular Smart Account Architecture

[hadv]

Summary

Implements ERC-7579 Modular Smart Account architecture for EthAura.

Changes

Phase 2: Core Account

• AuraAccount.sol - ERC-7579 compliant modular smart account
• AuraAccountFactory.sol - Factory using Solady's canonical ERC1967Factory

Phase 3: Modules

Validators (src/modular/modules/validators/)

• P256MFAValidatorModule.sol - Owner ECDSA + passkey MFA validation
• SessionKeyValidatorModule.sol - Session key management with time bounds, target/selector restrictions, and spending limits

Executors (src/modular/modules/executors/)

• SocialRecoveryModule.sol - Guardian-based recovery with 24-hour timelock
• HookManagerModule.sol - Dynamic hook management
• LargeTransactionExecutorModule.sol - Timelocked large transactions

Hooks (src/modular/modules/hooks/)

• MultiHook.sol - Aggregates multiple hooks
• LargeTransactionGuardHook.sol - Guards large transactions

Fallback (src/modular/modules/fallback/)

• ERC721ReceiverModule.sol - ERC-721 token receiver
• ERC1155ReceiverModule.sol - ERC-1155 token receiver

Testing

• 87 tests passing
• Covers all modules and core account functionality

Folder Structure

src/modular/
├── AuraAccount.sol
├── AuraAccountFactory.sol
└── modules/
    ├── validators/
    │   ├── P256MFAValidatorModule.sol
    │   └── SessionKeyValidatorModule.sol
    ├── executors/
    │   ├── HookManagerModule.sol
    │   ├── LargeTransactionExecutorModule.sol
    │   └── SocialRecoveryModule.sol
    ├── hooks/
    │   ├── MultiHook.sol
    │   └── LargeTransactionGuardHook.sol
    └── fallback/
        ├── ERC721ReceiverModule.sol
        └── ERC1155ReceiverModule.sol

Closes #148, #154, #155