feat: add SimpleKeyringV2 (#409)

Related to: https://consensyssoftware.atlassian.net/browse/MUL-1319

## Examples

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<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Introduce `SimpleKeyringV2` wrapping legacy `SimpleKeyring` to expose
the unified Keyring V2 API with EOA support, private-key import/export,
request handling, and robust concurrency/rollback.
> 
> - **@metamask/eth-simple-keyring**:
> - **New Adapter**: Add `SimpleKeyringV2` extending `EthKeyringWrapper`
to expose EOA accounts via `KeyringV2`.
> - Supports private-key import (hex) and export; maintains
`KeyringAccount` registry.
> - Routes requests for `eth_signTransaction`, `eth_sign`,
`personal_sign`, `eth_signTypedData_v1/v3/v4`,
`eth_getEncryptionPublicKey`, `eth_decrypt`, `eth_getAppKeyAddress`,
`eth_signEip7702Authorization`.
> - Adds mutex-based concurrency control and transactional rollback for
safe imports; implements account deletion.
> - **Tests**: Add comprehensive tests for account CRUD, exports,
request handling, concurrency, and registry syncing.
> - **Build/Deps**: Add deps `@metamask/keyring-api`, `async-mutex`;
update TS project references; update CHANGELOG.
> - **@metamask/keyring-api**:
> - Update `KeyringWrapper` docs to reference the account "registry"
(not "resolver").
> - **README**:
> - Update dependency graph to add `eth_simple_keyring --> keyring_api`.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
a6aef0d. This will update automatically
on new commits. Configure
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<!-- /CURSOR_SUMMARY -->

Author: mathieuartu

README.md

@@ -57,6 +57,7 @@ linkStyle default opacity:0.5
   eth_hd_keyring --> account_api;
   eth_ledger_bridge_keyring --> keyring_utils;
   eth_qr_keyring --> keyring_utils;
+  eth_simple_keyring --> keyring_api;
   eth_simple_keyring --> keyring_utils;
   eth_trezor_keyring --> keyring_utils;
   keyring_internal_api --> keyring_api;

packages/keyring-api/src/api/v2/wrapper/keyring-wrapper.ts

@@ -142,7 +142,7 @@ export abstract class KeyringWrapper<
    * Implementations are responsible for interpreting the
    * {@link CreateAccountOptions} (for example BIP-44 derivation or
    * private-key import) and returning the resulting {@link KeyringAccount}
-   * objects. Implementors should also ensure that the resolver is updated so
+   * objects. Implementors should also ensure that the registry is updated so
    * that {@link getAccount} works for newly created accounts.
    */
   abstract createAccounts(
@@ -154,7 +154,7 @@ export abstract class KeyringWrapper<
    * keyring.
    *
    * Implementations are expected to translate the ID to an underlying
-   * address (typically via the resolver) and then invoke the appropriate
+   * address (typically via the registry) and then invoke the appropriate
    * removal mechanism on the legacy keyring.
    */
   abstract deleteAccount(accountId: AccountId): Promise<void>;

packages/keyring-eth-simple/CHANGELOG.md

@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Add `SimpleKeyringV2` class implementing `KeyringV2` interface ([#409](https://github.com/MetaMask/accounts/pull/409))
+  - Wraps legacy `SimpleKeyring` to expose accounts via the unified `KeyringV2` API and the `KeyringAccount` type.
+  - Extends `EthKeyringWrapper` for common Ethereum logic.
+
 ## [11.0.0]
 
 ### Changed

packages/keyring-eth-simple/package.json

@@ -46,7 +46,9 @@
   "dependencies": {
     "@ethereumjs/util": "^9.1.0",
     "@metamask/eth-sig-util": "^8.2.0",
+    "@metamask/keyring-api": "workspace:^",
     "@metamask/utils": "^11.1.0",
+    "async-mutex": "^0.5.0",
     "ethereum-cryptography": "^2.1.2",
     "randombytes": "^2.1.0"
   },