merge(milestone): v1.29 Reposplit + Identity Layer Bring-Live to main (release v1.28.6)

---ci---
project: acdl
phase: 6
milestone: v1.29
status: complete
---/ci---

.ciagent/ARCHITECTURE.md

@@ -656,4 +656,69 @@ template (raw dict → JSON, no troposphere dep), presents for review
 (`$PAGER` + resource summary), requires explicit `y/N` approval before
 `cloudformation deploy --capabilities CAPABILITY_IAM`. `--check` reports
 prerequisites + IAM policy delta; `--verify` runs the KMS round-trip
-test. New IAM grants required: `cloudformation:*`, `codeartifact:*`.
+test. New IAM grants required: `cloudformation:*`, `codeartifact:*`.
+
+### §12.11 — Platform Ops Reposplit (v1.29, current)
+
+Platform operations are a Terraform-controlled discipline that lives
+outside the engineering repo, grounded in Vision §4 (Domain
+Boundaries — *the platform begins where the artifact is compiled and
+ends where it runs in production under operational guardrails*). Two
+repos, two ownership surfaces:
+
+- **`acdl/acdl` (GitHub)** — engineering. Authors `publish.yml` + the
+  artifacts (Lambda zip, layer wheel, Python wheel, ECR container
+  image with the static `kj` binary). Each tag `v1.29.x` produces a
+  GitHub Release with SHA-256-verified artifacts (REQ-354, D-235
+  tag-pin handoff). Engineering ends at the compiled artifact.
+- **`nova-platform-ops` (Gitea-private, OPER-PRIV, REQ-359)** —
+  operations. Authors the Terraform modules
+  (`networking`/`kms`/`identity`/`contract-ingest`/`bootstrap`/`edge`)
+  that bring those artifacts live in `581513795199`. Operations begins
+  at the live platform under guardrails. No GitHub mirror; CIAgent has
+  no presence there.
+
+The handoff between the two repos is the **tag-pin** (D-235):
+`nova-platform-ops` declares `local.nova_platform_version` +
+`local.kj_source_sha` and resolves substrates through a single
+`data.aws_ecr_image.kj_image`.
+
+**The `kj` substrate (KJ-LOCKSTEP, REQ-371):** `kj` (a compiled Go
+binary, pinned v0.0.3 in `platform/abac/kj-version.txt`, distinct from
+the kyverno-json engine) has exactly **one identity**: one ECR image
+digest shared by the production Lambda runtime
+(`aws_lambda_function.nova_idp_token_vend.image_uri`) and its
+defensive Fargate fallback
+(`aws_ecs_task_definition.kj.container_definitions[0].image`). A
+`lifecycle.precondition` on both image-bearing resources enforces at
+every `terraform plan` that both `image_uri` attributes resolve to the
+same digest via `data.aws_ecr_image.kj_image`. No second pipeline, no
+second SHA pin (D-238). KJ-STATIC: the binary is compiled
+`CGO_ENABLED=0` and `file(1)` reports `statically linked, no shared
+library` before embedding.
+
+**Covered-reference REQ tracking pattern:** the 14 covered-reference
+REQs (355-366, 371) are authored in `nova-platform-ops` (out-of-band).
+CIAgent in `acdl` tracks them for milestone completeness; their
+verification surface is the M1/M1.5/M2 cutover gates documented in
+the operator guide. The operator guide lists each covered-reference
+REQ with its gate entry + verification command + a "Result" column
+that the operator attests after running the gate in
+`nova-platform-ops` CI. P6 audit verifies every covered-reference REQ
+has a non-empty, green Result (grill CF-2/G-5). M1.5 green (3
+consecutive rebuilds of the 12-item spike, operator-attested in the
+guide) is the HARD P6 ship gate (grill CF-1/G-2.1).
+
+**Operator guide pointer:** `docs/operator-guide-platform-ops.md`
+(REQ-OPS-GUIDE) — the operator-facing runbook covering the Day-0
+cutover, M1.5 verification gate, M2 handoff loop, rollback, KMS
+rotation, JWKS reachability via CloudFront edge (INV-18), PITR
+restore, PAT revocation, edge config, Fargate standby health, cost,
+artifact-mirror fallback, and the cutover gates table.
+
+**JWKS edge (INV-18, D-233):** the JWKS endpoint is the only public
+read surface of the live platform. CloudFront + OAC pinning
+(`AuthType: AWS_IAM` on the Function URL — NOT `NONE`,
+`OriginAccessControlOriginType: lambda`, `SigningBehavior: always`)
+replaces direct Lambda Function URL exposure. Direct Function URL →
+403; via-CloudFront → 200.