Add sequencer wallet extension

[tuler]

Summary

• Add @cartesi/viem/sequencer, a viem Wallet Client extension for EIP-712 signed Cartesi sequencer transactions
• Provide sendSequencerTransaction, signSequencerTransaction, and submitSequencerTransaction actions for combined and split sign/submit flows
• Support both JSON-RPC accounts such as MetaMask and viem local accounts through viem's signTypedData action
• Validate transaction fields and expose structured request, response, and sequencer rejection errors
• Export the sequencer entrypoint in both ESM and CommonJS builds and add a release changeset
• Document browser-wallet and local-account setup, action semantics, EIP-712 fields, configuration, errors, and retry considerations

Testing

• Biome checks pass
• TypeScript checks pass
• Sequencer test suite passes (9 tests), including the MetaMask/EIP-1193 signing path
• ESM and CommonJS builds pass, including package export smoke checks
• Vocs production documentation build passes

[changeset-bot]

🦋 Changeset detected

Latest commit: 580fddf

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@cartesi/viem	Minor
@cartesi/wagmi	Patch

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Click here if you're a maintainer who wants to add another changeset to this PR

[tuler]

Example usage snippet (in the docs).

import { sequencerActions } from "@cartesi/viem/sequencer";
import { createWalletClient, custom, type Address } from "viem";
import { mainnet } from "viem/chains";

const [account] = (await window.ethereum.request({
  method: "eth_requestAccounts",
})) as [Address, ...Address[]];

const walletClient = createWalletClient({
  account,
  chain: mainnet,
  transport: custom(window.ethereum),
}).extend(
  sequencerActions({
    application: "0x...",
    url: "https://sequencer.example.com",
  }),
);

const receipt = await walletClient.sendSequencerTransaction({
  data: "0x...",
  maxFee: 1_200,
  nonce: 0,
});

[tuler]

I see there is a placeholder for a typescript client at https://github.com/cartesi/sequencer/tree/main/sdk/ts-client
If you think it makes more sense to move this code there let me know.