Gloas/SIP-94: pick a current default for ProposerPreferences target_gas_limit; DefaultGasLimit (30M) is stale and diverges from the node (36M)

[shane-moore]

Context

SIP-94 (§5) deprecates the ValidatorRegistration duty at the Gloas fork and replaces it with ProposerPreferences, which carries a TargetGasLimit field (#632 constants, #633 implementation). The ProposerPreferences runner is not implemented in ssv-spec yet (only the types/gloas type has landed in #633), so nothing populates TargetGasLimit on the spec side today.

Problem

The default gas-limit values are stale and fragmented:

• types.DefaultGasLimit = 30_000_000 (types/beacon_types.go:37) is two generations behind mainnet: the network gas limit has been 60M since 2025-11-25 (30M → 45M → 60M). It is the default for the RoleValidatorRegistration runner (types/testingutils/runner.go), the duty SIP-94 deprecates at Gloas.
• When the types: ePBS (Gloas / SIP-94) reference implementation — WIP #633 ProposerPreferences runner lands it needs a TargetGasLimit default for the operator-unset case, and there is no spec constant sized for current mainnet.
• The node (ePBS (EIP-7732 / Gloas) — SIP-94 ssv#2901) already implements the runner: it defaults TargetGasLimit to operator config (opts.GasLimit) with a fallback to a node-side DefaultGasLimit = 36_000_000 (protocol/v2/ssv/runner/validator_registration.go:35, reused at proposer_preferences.go:379). That is a separate constant from the spec's 30M, so spec and node disagree, and 36M is itself stale vs 60M.

Ask

1. Set the ProposerPreferences target_gas_limit default (operator-unset case) to 60M when the types: ePBS (Gloas / SIP-94) reference implementation — WIP #633 runner lands, sourced from a spec constant.
2. Decide the fate of types.DefaultGasLimit: bump to 60M so the spec tracks mainnet and both runners share one current value, or leave it frozen as the pre-Gloas ValidatorRegistration default. A bump changes ValidatorRegistration signing roots, so it requires regenerating the spec-test JSON fixtures.
3. Reconcile the value with the node's 36M so spec and node agree on the default a cluster applies when an operator does not override.

Refs

• SIP-94 §5: ePBS (EIP-7732) Support SIPs#94
• ssv-spec types: add ePBS (Gloas) domains, roles, and partial-sig types #632 (wire constants), types: ePBS (Gloas / SIP-94) reference implementation — WIP #633 (Gloas types / ProposerPreferences)
• ePBS (EIP-7732 / Gloas) — SIP-94 ssv#2901 (node-side ProposerPreferences runner)
• Mainnet gas limit has been 60M since 2025-11-25.