feat: sign DKLS safe VRF keygen messages and send BIP44 path on safe derive

[davidkaplanbitgo]

Tickets: WCN-3084, WCN-2969

Two commits, two independent changes to the safe MPC flows in sdk-core:

1. feat: align DKLS safe VRF keygen with the HSM (WCN-3084)
2. feat(sdk-core): send the full BIP44 path on safe derive round 1 (WCN-2969)

The first commit is the work from #9982 (branch sibikrishnan/wcn-3084-dkls-vrf-keygen-signed-messages), brought in here so both land together.

1. DKLS safe VRF keygen signed messages (WCN-3084)

• Safe ecdsaMpc keygen fails at R1: the HSM returns 400 because the VRF messages are sent as unsigned base64(JSON) strings.
• Sign each party's VRF message with its GPG key (DklsComms.detachSignData), in the {from, message, signature} shape the HSM verifies.
• Verify BitGo's signature on bitgoVrfMsg1. Decrypt and verify bitgoVrfMsgToUser / bitgoVrfMsgToBackup.
• R2 sends only each party's opening addressed to BitGo, signed.
• Remove the nonexistent bitgoVrfMsg2 assertion, the local opaque VRF types, and the serialize helpers.
• The fake HSM in the tests follows the hsm-api contract, with cases for a forged R1 commitment and forged R2 openings.

2. Full BIP44 path on safe derive round 1 (WCN-2969)

• ECDSA and EdDSA sendDerivationRound1BySender send the Safe child path (m/44'/<coinType>'/<slot>'/<account>') in place of the account index. Removes the TODO(WCN-2969) markers.
• KeyGenSenderForSafeChild (both curves) now takes and sends coin, so wallet-platform can resolve the coin type it expects in the path.
• The EdDSA createSafeChildKeychains keeps validating the path with parseSafeBip44Path before any network call.

Dependency bump

@bitgo/public-types 6.83.0 to 6.90.0 in sdk-core, sdk-lib-safes, abstract-lightning, express, passkey-crypto, sdk-coin-flrp, sdk-coin-sol and bitgo. 6.88.0 added the DKLS VRF codecs (change 1); 6.90.0 adds path on the derive round 1 requests (change 2).

Depends on

• Merge after the matching wallet-platform change for the signed VRF messages is deployed: each side rejects the other's old format (safe ecdsaMpc only; it already fails today).
• wallet-platform accepting path and coin on POST /mpc/generatekey (bitgo-microservices draft PR, WCN-2963).

Test

• Root yarn build passes.
• bitgo test/v2/unit/internal/tssUtils/ecdsaVrfMPCv2/: 13 passing (createKeychains.ts for change 1; the R1 nock in createSafeChildKeychains.ts matches path and coin for change 2).
• sdk-core unit tests filtered to VRF|Vrf|derive|Derive|safe: 130 passing (includes eddsaVrfMPCv2.ts: R1 body carries path and coin, no derivationIndex).
• Not run against a real HSM or wallet-platform.

[linear-code]

WCN-2969

[github-actions]

⚠️ Unit tests are failing on Node 26.x (Current release line, non-blocking). This is not an LTS version yet, so it does not block merge, but it signals an incompatibility to fix before Node 26.x becomes LTS.

View run

[melizafranco]

Breaking change linter override approved. Re: Pre-GA. Note that the Audit API CI will continue to show as failing. That’s expected, but non blocking now.