feat(me): add EdDSA MPCv2 AWM client method

[Marzooqa]

What

• Add a single eddsaMPCv2KeyGen method to AdvancedWalletManagerClient in src/masterBitgoExpress/clients/advancedWalletManagerClient.ts, parameterized by shareType (initialize, round1, round2, finalize)
• Posts to the AWM route POST /api/{coin}/eddsampcv2/keygen/{shareType} (WCI-892)
• Returns EddsaMPCv2KeyGenResponseType; optional request fields mirror the AWM API spec codecs

Why

• WCI-893 of the EdDSA MPCv2 external-signer key generation plan (WCI-888): Master Express needs a typed client method for each AWM round
• Single method (not three, as on the stale WCI-895 branches) — the WCI-895 callback factory calls it once per shareType

Dependencies

• Stacked on feat(awm): add EdDSA MPCv2 key generation handler, types and route #282 (WCI-892, the AWM handler + route). The v1.eddsampcv2.keygen route and its request/response types only exist on that branch.

Test plan

• Thin HTTP wrapper — exercised by the WCI-895 callback factory tests (per ticket scope)
• tsc --noEmit clean against the beta SDK (8.2.1-beta.2107)

Ticket: WCI-893

[linear-code]

WCI-893