feat: add support for redelegating from permission contexts

[jeffsmale90]

📝 Description

This PR implements support for creating redelegations from existing permission contexts (e.g., ERC-7715 responses), significantly improving the developer experience when working with delegation chains.

Previously, developers had to manually decode permission contexts, extract the leaf delegation, sign a new delegation, and re-encode the chain. This PR streamlines that workflow with new APIs and improved type safety.

🔄 What Changed?

Core API Enhancements (createDelegation / createOpenDelegation)

• Added parentPermissionContext parameter to createDelegation and createOpenDelegation

  • Accepts a PermissionContext (either a Delegation[] or encoded Hex)
  • Automatically extracts the leaf delegation (first element in the chain) to use as the parent authority
  • Uses a discriminated union with parentDelegation and scope so the three options are mutually exclusive at the type level

• Made scope optional when a parent delegation/permission context exists

  • When redelegating, scope can be inherited from the parent
  • Scope constraints are still enforced through the parent's caveats in the chain
  • An explicit scope override is still supported when you want to add additional scope-derived caveats

• resolveCaveats now takes hasInheritance

  • Throws Scope is required when the delegation has no inheritance when scope is missing on a root delegation
  • When inheriting, falls back to a base caveat builder (no scope caveats appended)

New Redelegation Actions

Two explicit, high-level convenience functions that handle the full redelegation workflow. They mirror the createDelegation / createOpenDelegation split so callers always get the kind of delegation they expect — no optional to flag deciding the shape of the result.

• redelegatePermissionContext — creates a redelegation to a specific delegate (to is required).
• redelegatePermissionContextOpen — creates an open redelegation (delegate is ANY_BENEFICIARY); does not accept to.

Both functions:

1. Decode the permission context
2. Extract the leaf delegation as the parent
3. Create a new delegation (specific or open) inheriting from it
4. Sign it via signDelegation
5. Prepend it to the chain and re-encode
6. Return both the signed delegation and the encoded permissionContext

Shared parameters:

• account? — defaults to client.account
• environment — provides DelegationManager and caveat enforcers
• permissionContext — the context to redelegate from
• chainId — chain id used for the EIP-712 signature
• scope? — optional override; inherits from parent when omitted
• caveats? — additional caveats to apply
• salt? — optional salt for uniqueness

redelegatePermissionContext additionally requires:

• to — the address of the new delegate

Client Extension (redelegatePermissionContextActions)

• Follows the existing SDK pattern (e.g., signDelegationActions)
• Adds both redelegatePermissionContext and redelegatePermissionContextOpen to the wallet client when .extend()-ed
• Automatically infers chainId from client.chain.id for both actions (throws Chain ID is required if neither client chain nor chainId is provided)

Type Safety

• The BaseCreateDelegationOptions type uses a discriminated union so exactly one of the following is allowed:
  • scope (root delegation, no parent)
  • parentDelegation (with optional scope)
  • parentPermissionContext (with optional scope)
• The two redelegation actions are independent functions with distinct parameter types (RedelegatePermissionContextParameters vs RedelegatePermissionContextOpenParameters), so the choice between specific and open is made at the call site rather than via an optional flag.

🚀 Why?

Issue: #196

Before this PR, redelegating from an ERC-7715 response required manual orchestration:

const erc7715Response = {...};

const decodedContext = decodeDelegations(erc7715Response.context);
const leafDelegation = decodedContext[0];

const newDelegation = createDelegation({
  environment,
  scope: erc20Scope, // had to manually re-specify scope
  to: charlie.address,
  from: bob.address,
  parentDelegation: leafDelegation,
  caveats: [timestampCaveat],
});

const signature = await signDelegation(walletClient, {
  delegation: newDelegation,
  delegationManager: environment.DelegationManager,
  chainId: 11155111,
});

const signed = { ...newDelegation, signature };
const newContext = encodeDelegations([signed, ...decodedContext]);

Now, you can use the parentPermissionContext parameter on createDelegation:

import {
  createDelegation,
  decodeDelegations,
  encodeDelegations,
  signDelegation,
} from '@metamask/smart-accounts-kit';

const erc7715Response = {...};

const redelegation = createDelegation({
  environment,
  from: bob.address,
  to: charlie.address,
  parentPermissionContext: erc7715Response.context,
  caveats: [timestampCaveat],
});

const signature = await signDelegation(walletClient, {
  delegation: redelegation,
  delegationManager: environment.DelegationManager,
  chainId: sepolia.id,
});

const newPermissionContext = encodeDelegations([
  { ...redelegation, signature },
  ...decodeDelegations(erc7715Response.context),
]);

Or, use the dedicated actions to redelegate directly:

import { redelegatePermissionContextActions } from '@metamask/smart-accounts-kit/actions';
import { createWalletClient, http } from 'viem';
import { sepolia } from 'viem/chains';

const erc7715Response = {...};

const walletClient = createWalletClient({
  account: bob,
  chain: sepolia,
  transport: http(),
}).extend(redelegatePermissionContextActions());

const { delegation, permissionContext } =
  await walletClient.redelegatePermissionContext({
    environment,
    permissionContext: erc7715Response.context,
    to: charlie.address,
    caveats: [timestampCaveat],
  });

await sendUserOperationWithDelegation(client, {
  calls: [
    {
      to: contractAddress,
      data: callData,
      permissionContext,
      delegationManager: environment.DelegationManager,
    },
  ],
});

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