Support for EIP712

Hello,

I was reviewing the code and noticed that the wallet abstraction relies on the Web3 library. However, from what I understand, transaction broadcasting is currently handled through Coinbase endpoints.

I wanted to check whether it would be possible to integrate a signing method using [LocalAccount.sign_typed_data](https://eth-account.readthedocs.io/en/stable/eth_account.signers.html#eth_account.signers.local.LocalAccount.sign_typed_data) or [web3.eth.sign_typed_data](https://web3py.readthedocs.io/en/stable/web3.eth.html#web3.eth.Eth.sign_typed_data) for EIP-712 transactions. While I believe I could implement the signing process, I’m unsure how transaction submission would fit within the existing structure.

Is this something already planned or in progress? I'd appreciate any insights on whether this approach aligns with your architecture or if there are any blockers I should consider.

Thanks!