SEC-140: Generate unified Ethereum client configuration

[huangminghuang]

Summary

• Updated this branch through current master (ad346700) and adopted the
  final host-side configuration shape delivered by
  wire-sysio#531.
• Generate the versioned data/ethereum-client.json ProtoJSON artifact for
  batch-operator and underwriter daemons, passed through
  --outpost-ethereum-client-config-file. Artifact preparation is shared by
  create, run, restart, and flow paths; bios and producer-only nodes receive
  neither an Ethereum signing client nor that option.
• Keep this host-only Ethereum client configuration local to wire-tools-ts.
  SEC-131 intentionally keeps it outside the shared OPP model bundles used by
  Solidity and Solana, so this PR neither changes wire-sysio nor publishes a
  generated model package.
• Local Anvil artifacts contain a finite nested transaction_policy: 2 gwei
  priority fee, 100 gwei maximum fee, 6,000,000 final gas limit, and 0.7 ETH
  total native cost. The total covers the 0.6 ETH maximum gas spend and leaves
  0.1 ETH for transaction value; regression coverage checks the 5,270,438-gas
  buffered remote epochIn high-water mark.
• External-outpost artifacts deliberately omit transaction_policy; the
  operator of that endpoint selects production limits outside wire-tools-ts.
  The obsolete standalone configuration helpers and legacy
  --outpost-ethereum-client path are removed.
• Include the current typed challenge_id default in the shared underwriting
  request test fixture, restoring compatibility with the released SDK contract
  types and resolving SEC-151.

Validation

• Focused policy/configuration/artifact coverage: 4 Jest suites, 34 tests
  passed with Node 24.15.0.
• After synchronizing and rebuilding the linked @wireio/sdk-core@1.0.84, the
  complete pnpm test gate passed: build plus 221 Jest suites / 1,708 tests.
  pnpm lint and git diff --check also passed. SEC-151 is Done.
• The historical remote pass for superseded SHA 29287522 is not used as
  final evidence. A replacement remote E2E run will target this PR's final
  pushed head and be linked here when it passes.

Dependency

Requires merged wire-sysio#531,
which provides the nodeop nested-client loader and enforcement. No companion
wire-sysio PR is required.

Jira: SEC-140