web-examples feat: erc 6492 signature validation

PR Documentation Outline: Title: Add ERC-6942 Signature Validation for Pre-Deployed Contracts

Summary: This PR implements signature validation using ERC-6942, which enables verifying signatures for smart contract wallets even when they aren't deployed. This is necessary because some wallets delay contract deployment until the first transaction. By adopting ERC-6942, we validate signatures before wallet deployment.

Details:

isValidateSignature() currently validates deployed contract signatures.
ERC-6942 allows signature verification even when a contract is in the pre-deployment state.
This approach avoids delayed wallet interactions and enhances user experience.

Technical Changes:

Added new validation logic in accordance with ERC-6942 standards.
Ensured backward compatibility with already deployed contracts.

Changes Made:

Added signature verification logic compatible with ERC-6942.
Updated the isValidateSignature() method to support both deployed and pre-deployed contract signatures.
Comprehensive testing for deployed and pre-deployed wallet scenarios.

Why This Change? Some smart contract wallets only deploy upon the first transaction. With ERC-6942, we can validate signatures before deployment, ensuring users experience seamless wallet interactions.

This diagram shows the two flows:

Deployed Contract: Traditional signature verification for deployed wallets. Pre-Deployed Contract (ERC-6942): Signature verification for wallets that haven't been deployed yet.

eip6492 drawio