chore: support tokenApproval for MPC

[kamleshmugdiya]

Ticket: COIN-4071

[sampras-saha]

@claude can you review?

[sampras-saha]

LGTM

[Copilot]

Pull Request Overview

Adds support for ERC20 token approvals within MPC flows and the Wallet API.

• Introduces a new tokenApproval intent across TSS utils and MPC utilities.
• Updates PopulatedIntent and AbstractEthLikeNewCoins to recognize and pass tokenName.
• Adds unit tests covering populateIntent and approveErc20Token for Ethereum, Polygon, and BSC.

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
modules/sdk-core/src/bitgo/wallet/wallet.ts	Added tokenApproval case in the prebuild transaction switch.
modules/sdk-core/src/bitgo/utils/tss/baseTypes.ts	Extended PopulatedIntent interface with optional tokenName.
modules/sdk-core/src/bitgo/utils/mpcUtils.ts	Supported tokenApproval in populateIntent and included tokenName.
modules/abstract-eth/src/abstractEthLikeNewCoins.ts	Allowed tokenApproval in missing-params validation logic.
modules/bitgo/test/v2/unit/wallet.ts	Added tests for populateIntent and the approveErc20Token method.

Comments suppressed due to low confidence (3)

modules/sdk-core/src/bitgo/wallet/wallet.ts:3358

• Consider adding a unit test to verify that prebuildTxWithIntent is called with the correct intentType and tokenName for the tokenApproval case, ensuring this branch remains covered.

      case 'tokenApproval':

modules/sdk-core/src/bitgo/utils/tss/baseTypes.ts:259

• [nitpick] The new tokenName field should be documented in the interface JSDoc to explain its purpose and any constraints (e.g., valid tokens, format).

  tokenName?: string;

modules/bitgo/test/v2/unit/wallet.ts:5096

• This test checks for a generic rejection but doesn't assert the specific error message. To strengthen validation, specify the expected error message when required parameters are missing.

      await ethWallet.approveErc20Token('', tokenName).should.be.rejectedWith();

[Copilot]

[nitpick] The tokenApproval branch re-adds tokenName to the returned intent even though it's already included in baseIntent. Consider merging feeOptions and tokenName into baseIntent or extracting common fields to reduce duplication.

Suggested change

tokenName: params.tokenName,

[Copilot]

[nitpick] The list of supported transaction types is hard-coded in multiple places. Extract this array into a shared constant to ensure consistency and simplify future updates.

Suggested change

	(txParams.type && ['acceleration', 'fillNonce', 'transferToken', 'tokenApproval'].includes(txParams.type))
	(txParams.type && SUPPORTED_TRANSACTION_TYPES.includes(txParams.type))