[DEFERRED] Remote signer and multiple Builder keys

[krisoshea-eth]

Remote-signing compatibility watch, 13 September

Nico's Lodestar PR 10071 aligns validator-side Gloas signing messages with remote-signing-api 28 and Web3Signer 1192. It wraps envelope, PTC message, proposer-preference and request-auth data with the fork version and renames the PTC message signing type. The added real-Web3Signer cases are skipped until the test image supports Gloas. This is not remote signing for the standalone Builder's locally held key, and does not activate this deferred package. Reuse the accepted wire contract if remote Builder signing is later selected; do not infer live compatibility from skipped tests.

Status

Tracking shell only. This is not current core work and must not be started without explicit maintainer promotion and bounded rescoping.

Why it remains useful

Production operation may require stronger key isolation and more than one Builder identity.

Activation trigger

• A Builder signer and key-management specification or supported signer exists.
• Multi-key selection and balance semantics are settled.
• Maintainers approve the contract.
• A scoped Conditional package with owner, reviewer, evidence, and stop rule is approved.

Boundary

Do not infer a Builder remote-signing contract from incomplete validator remote-signing behavior. Core supports one local Builder keystore.

[linear-code]

LOD-39