* Add seahaven-security member baseline (Phase 3)
Account 001520130573 is the org's delegated security administrator.
Same member-baseline construct set as external-dev; own CD job under
its own OIDC role. Created at org root pending manual root hardening
before the OU move (deny-root-user invariant).
* Document delegated security administration runbook
Delegation to seahaven-security has no CloudFormation types; the CLI
sequence is the record, same pattern as the other account toggles.
* Apply Phase-3 security-review findings
Delegation runbook marked PENDING with hard preconditions (baseline
deployed, root MFA verified, account inside the security OU) — it had
read as applied before execution, the org's known claimed-done-but-NOT
failure mode (SEC-BASE-A/B). New security-guardrails SCP on the
security OU: region lock, IAM user/key lockout, privileged-role
protection, delegated-admin membership protection (SEC-BASE-C,
cross-reviewed APPROVE). deploy-security gains stack-name pre-flight
(SEC-BASE-D). Default VPC in 001520130573 deleted; empty flow-log list
and aws@ alert routing documented as deliberate (SEC-BASE-F/H).
cdk import by Id (non-mutating), content byte-exact from
describe-policy, targetIds = exact live attachments. Post-import drift
detection: IN_SYNC, 0 drifted. All four Retain — the full org guardrail
set is now drift-checked IaC.
* Add org-governance stack: OU skeleton + generalized SCPs
Phase 2 of the multi-account segregation plan: codifies the OU tree
(workloads/prod/nonprod, security, sandbox, graveyard) and three
org-wide SCPs (workloads-region-lock, protect-security-baseline,
deny-root-user) generalized from the proven external-dev guardrails.
All resources Retain — CFN must never detach a live guardrail. New SCPs
attach only to the new empty OUs; extending to external-dev is a
separate gated targetIds change after live verification.
* Record SCP cross-review dispositions in org-governance
Root hardening must precede the OU move (deny-root-user blocks root MFA
enrollment), delegated-admin flows ride service-linked roles that SCPs
never evaluate, and the cdk exec-role exemption is accepted risk
mirroring the external-dev guardrails.
* Add org-governance to the management deploy job
Explicit stack selectors require every new stack to join exactly one
CD job (SH-ORG-005 discipline documented in this file).
