docs: add Openfort as a signer option

[emauja]

Summary

This PR adds documentation for using Openfort embedded wallets as a signer with ZeroDev Kernel accounts.

Changes

• Added docs/pages/sdk/signers/openfort.mdx - documentation for current SDK
• Added docs/pages/sdk/v5_3_x/signers/openfort.mdx - documentation for SDK v5.3.x
• Updated vocs.config.tsx to include Openfort in the sidebar under Auth Providers

About Openfort

Openfort is a wallet infrastructure platform that provides:

• Non-custodial embedded wallets - wallets are self-custodial by design
• Multiple authentication options - passkeys, social login, email
• EIP-1193 compatible provider - works seamlessly with viem, wagmi, and ethers
• Built-in ERC-4337 support - smart accounts with gas sponsorship, batching, and session keys

Integration Pattern

The integration follows the same pattern as other providers (Dynamic, Privy, Turnkey):

1. Initialize Openfort client
2. Authenticate user
3. Get EIP-1193 provider via openfort.embeddedWallet.getEthereumProvider()
4. Pass provider to ZeroDev's signerToEcdsaValidator

Testing

The code examples have been reviewed against Openfort's documentation to ensure accuracy.

[vercel]

@jahanzeb1018 is attempting to deploy a commit to the zero-dev1 Team on Vercel.

A member of the Team first needs to authorize it.

[SahilVasava]

Thanks for adding Openfort as a signer option! The docs are well-written and the integration pattern is solid. A couple of issues to fix:

Bug: useOpenfortAuth doesn't exist — should be useUser

In both docs/pages/sdk/signers/openfort.mdx and docs/pages/sdk/v5_3_x/signers/openfort.mdx, the "Full example with authentication" section uses:

import { OpenfortButton, useOpenfortAuth } from "@openfort/react";
const { isAuthenticated } = useOpenfortAuth();

The correct hook is useUser() (ref: official Openfort 7702 recipe):

import { OpenfortButton, useUser } from "@openfort/react";
const { isAuthenticated } = useUser();

Minor: Missing accountType in walletConfig

The official Openfort examples include accountType: AccountTypeEnum.EOA in the walletConfig. Consider adding it to the provider setup examples:

import { AccountTypeEnum } from "@openfort/react";

walletConfig={{
  shieldPublishableKey: "YOUR_SHIELD_PUBLISHABLE_KEY",
  createEncryptedSessionEndpoint: "YOUR_BACKEND_ENDPOINT",
  accountType: AccountTypeEnum.EOA,
}}

Everything else looks good — the code examples are clear and the sidebar placement is correct.