[REVIEW-01] Close the #9781 foundation review and lifecycle implementation

[krisoshea-eth]

Why

Marko's completed CLI-01 and API-01 scopes remain closed. Lodestar PR #9781 merged on 14 August 2026, so REVIEW-01 now tracks only the explicit post-merge review-marker and accepted follow-up reconciliation that must not disappear from the project record.

The lifecycle design is implemented: an unknown or pending configured Builder remains inert and is polled with cancellation until it becomes active; an exited Builder fails distinctly. The standard API response path, identity sanity checks, readiness reporting, and BN/sidecar responsibility boundary are also recorded.

Planning

• Lane: Builder
• Gate: Gate A
• Priority: High
• Owner: Marko L
• Reviewer: Nico Flaig
• Related completed scopes: CLI-01 and API-01
• Remaining follow-up: TEST-01 plus explicit reconciliation of the twelve historical Lodestar PR 9781 review-thread markers
• Landed follow-ups: Lodestar issue 9819 closed through merged Lodestar PR 9826; Lodestar PR 9827, Lodestar PR 9848, Lodestar PR 9860, and Lodestar PR 9868 merged

Tasks

• Reconcile all twelve remaining review-thread markers on Lodestar PR #9781: five outdated threads, two accepted or already-applied threads, one test-helper follow-up tracked by #9819, and four logging or abort-loop nits carried by #9827.
• Implement the reviewed unknown-key behavior: remain inert and retry with cancellation until the configured key is deposited or activated.
• Preserve pending, exited, and unknown Builder states as distinct, operator-visible results.
• Use the API client's standard .value() response path and preserve useful API error details.
• Retain the current assumption that Gloas-capable clients expose the health endpoint; revisit it only if interoperability evidence exposes a gap.
• Document BN-authoritative inputs and the sidecar's sanity checks in the implementation plan and Living Technical Note.
• Keep TEST-01 responsible for broader behavioral regressions; close Lodestar issue 9819 through shared-helper PR Lodestar PR 9826 and MET-01 through metrics PR Lodestar PR 9848.
• Merge PR #9781 with passing required checks and record its final commit, approval, and release status.
• Land #9827 as ec596194e2 and close Lodestar issue 9819 through merged Lodestar PR 9826.
• Reconcile the corresponding historical #9781 markers without silently resolving maintainer feedback.

Done when

PR #9781's merged implementation and approval are recorded, all remaining review markers are explicitly reconciled, merged Lodestar PR 9826/Lodestar PR 9827 and completed MET-01 are recorded, the responsibility boundary is documented, and remaining tests are linked to TEST-01.

Evidence

• Merged PR: Lodestar PR #9781
• Docs reconciliation: docs: reconcile Builder foundation status
• Merge commit: 2a04194b900ef972c6f469d06017d5c972be5714
• Approved head: 3fe4ef4980645144668f8f634884c72a69f83677
• Review: Nico approved with "LGTM, mostly nits, nothing that should block merging this"
• Checks: required build, lint, type, unit, spec, browser, E2E, simulation, CodeQL, docs, and spec-reference checks passed
• Release status: unreleased; Lodestar v1.46.0 at 3873dd5b032d0ad82581fc3416e9628b4f6f2642 predates Lodestar PR 9781
• Review inventory on 14 August 2026: twelve unresolved GitHub thread markers remain; no maintainer thread was silently resolved
• Landed follow-ups: Lodestar issue 9819 closed through #9826 at cec7fd63e3; #9827 merged at ec596194e2; metrics #9848, CLI tests Lodestar PR 9860, and transient identity handling Lodestar PR 9868 are merged

[linear-code]

LOD-47