feat: add EthKeyringWrapper for common Eth logic around KeyringV2 implementation (#404)

<!--
Thanks for your contribution! Take a moment to answer these questions so
that reviewers have the information they need to properly understand
your changes:

* What is the current state of things and why does it need to change?
* What is the solution your changes offer and how does it work?

Are there any issues or other links reviewers should consult to
understand this pull request better? For instance:

* Fixes #12345
* See: #67890
-->

Related to: https://consensyssoftware.atlassian.net/browse/MUL-1316

## Examples

<!--
Are there any examples of this change being used in another repository?

When considering changes to the MetaMask module template, it's strongly
preferred that the change be experimented with in another repository
first. This gives reviewers a better sense of how the change works,
making it less likely the change will need to be reverted or adjusted
later.
-->

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Introduces `EthKeyringWrapper` with shared Ethereum `submitRequest`
logic and updates `HdKeyringV2` to extend it, adding RPC param structs,
an `EthKeyring` alias, tests, and required deps.
> 
> - **Keyring API**:
> - **New**: `eth/v2/EthKeyringWrapper` abstract class with common
Ethereum request routing (`submitRequest`) and `EthKeyringMethod` enum.
> - **RPC**: Add `EthGetEncryptionPublicKeyOptionsStruct` and
`EthGetEncryptionPublicKeyParamsStruct` (address, optional options).
> - **Exports**: Re-export from `eth/v2` and include new wrapper in
`eth/index`.
>   - **Deps**: Add `@ethereumjs/tx` and `@metamask/eth-sig-util`.
> - **Tests**: Add comprehensive unit tests for wrapper routing and
errors.
> - **Keyring ETH HD**:
> - **Refactor**: `HdKeyringV2` now extends `EthKeyringWrapper`; removes
duplicate routing, uses shared methods list including
encryption/app-key/EIP-7702.
> - **Tests**: Adjust to pass address/options for
`eth_getEncryptionPublicKey` and align with wrapper behavior.
>   - **Changelog**: Note extension of `EthKeyringWrapper`.
> - **Keyring Utils**:
>   - **New**: Export `EthKeyring` type alias for legacy `Keyring`.
>   - **Changelog**: Document alias addition.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
22051b5. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: mathieuartu

packages/keyring-api/CHANGELOG.md

@@ -9,6 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- Add `EthKeyringWrapper` abstract class for Ethereum-based `KeyringV2` implementations ([#404](https://github.com/MetaMask/accounts/pull/404))
+  - Provides common Ethereum signing method routing (`submitRequest`) for all Ethereum-based keyrings.
 - Add `KeyringWrapper` base class to adapt legacy keyrings to `KeyringV2` ([#398](https://github.com/MetaMask/accounts/pull/398))
 
 ### Changed

packages/keyring-api/package.json

@@ -46,6 +46,8 @@
     "test:watch": "jest --watch"
   },
   "dependencies": {
+    "@ethereumjs/tx": "^5.4.0",
+    "@metamask/eth-sig-util": "^8.2.0",
     "@metamask/keyring-utils": "workspace:^",
     "@metamask/superstruct": "^3.1.0",
     "@metamask/utils": "^11.1.0",

packages/keyring-api/src/eth/index.ts

@@ -3,3 +3,4 @@ export * from './erc4337';
 export * from './rpc';
 export * from './types';
 export * from './utils';
+export * from './v2';

packages/keyring-api/src/eth/rpc/params.ts

@@ -126,6 +126,14 @@ export type EthEip7702Authorization = Infer<
   typeof EthEip7702AuthorizationStruct
 >;
 
+/**
+ * A struct for getEncryptionPublicKey options.
+ */
+export const EthGetEncryptionPublicKeyOptionsStruct = record(
+  string(),
+  unknown(),
+);
+
 // ============================================================================
 // RPC Method Parameter Structs
 // ============================================================================
@@ -214,3 +222,11 @@ export const EthSignEip7702AuthorizationParamsStruct = tuple([
 export type EthSignEip7702AuthorizationParams = Infer<
   typeof EthSignEip7702AuthorizationParamsStruct
 >;
+
+/**
+ * Parameters for `eth_getEncryptionPublicKey`.
+ */
+export const EthGetEncryptionPublicKeyParamsStruct = tuple([
+  EthAddressStruct, // address
+  optional(EthGetEncryptionPublicKeyOptionsStruct), // options
+]);