feat: splitting signing methods into prepare and sign

[howydev]

Pull Request Checklist

• Did you add new tests and confirm existing tests pass? (yarn test)
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PR-Codex overview

This PR focuses on enhancing the signature handling in the account-kit smart contracts by introducing new types and methods for managing signature requests. It includes improvements for signing messages and typed data, ensuring better error handling and type safety.

Detailed summary

• Added SignatureRequest type with specific request types.
• Introduced SigningMethods type for signature preparation and formatting.
• Implemented assertNeverSignatureRequestType for error handling.
• Refactored nativeSMASigner and singleSignerMessageSigner to utilize new signing methods.
• Enhanced signing logic with clearer type checks and error handling.
• Updated method signatures to improve type safety and clarity.

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[Blu-J]

💬 try this with a this this is assuming we have we can infer the type from references to params sent down or

async signMessage(this: SigningMethods<'eth_signTypedData_v4'>, {message}: MessageTrait) {// do things}

or do an overloaded type definition based on the type

const signMessage: Type extends 'eth_signTypedData_v4' ? (value: MessageTrait) => RT : never
const  signMessage = async ({message}) {// do things};

[moldy530]

we need to update the ToSmartAccountParams or w/e it's called as well to support passing in the extensions

[moldy530]

also looking at this, I don't think those prepare and format methods are actually exposed because of this. they need to be passed in threw params and then added to the resulting object from toSmartContractAccount

[howydev]

drat.. will relook + add a test for this

[adamegyed]

Can we use the type declared in @account-kit/wallet-client? I'm not sure where it's exported, but I'm pretty sure this type exists somewhere else already.