feat(mbe): use customSigning fns for MPC eddsa

[pranavjain97]

Ticket: WP-5246

[Copilot]

Pull Request Overview

This PR implements custom signing functions for MPC EdDSA algorithms to enable proper integration with the enclaved express client. The main change is extending the existing ECDSA MPCv2 custom signing pattern to support EdDSA algorithms.

• Refactors sendMany handling to use custom signing functions for both ECDSA and EdDSA MPC algorithms
• Creates new EdDSA custom signing functions that maintain state between signing rounds
• Updates test coverage to reflect the new unified MPC signing approach

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/api/master/handlers/handleSendMany.ts	Refactors MPC signing logic to support both ECDSA and EdDSA with custom signing functions
src/api/master/handlers/eddsa.ts	Adds custom EdDSA signing function factory and updates existing handler to use them
src/api/master/clients/enclavedExpressClient.ts	Exports SignMpcCommitmentResponse interface for external use
src/__tests__/api/master/signAndSendTxRequest.test.ts	Adds comprehensive test coverage for both ECDSA and EdDSA signing workflows
src/__tests__/api/master/sendMany.test.ts	Updates EdDSA test to reflect new unified MPC approach
src/__tests__/api/master/eddsa.test.ts	Re-enables EdDSA tests and removes obsolete mocking

[Copilot]

The commitmentResponse variable is declared but not initialized, which could lead to runtime errors if customRShareGenerator or customGShareGenerator are called before customCommitmentGenerator. Consider initializing with undefined or adding explicit undefined checks.

Suggested change

	let commitmentResponse: SignMpcCommitmentResponse;
	let commitmentResponse: SignMpcCommitmentResponse | undefined = undefined;

[mohammadalfaiyazbitgo]

curious why you need to do this? Ideally your parameters should be a subset of SendManyOptions