ERC-4337 Configured chainId Not Enforced Before Building & Signing UserOperations

[nulllpc]

The wallet configuration declares a​​ chainId​, but the ​​ERC-4337 account never uses it to pin the signing​ ​context.​​ _getChainId() ​​reads​​ eth_chainId​​ from the​​configured provider, caches it, and returns it.​ _buildUserOperation() ​​then signs the​​ UserOperation ​​against that provider-reported value.​ Because the configured​​ chainId ​​is never compared to​​the provider's response, a provider that reports a​ ​chain ID other than the one the application configured causes the library to build and sign a​ UserOperation​​for that other chain