feat(policy): adopt security zone stances

Assistant: codex
Assistant-Model: gpt-5.6-sol
Assistant-Session: 01a0291a-1e87-7151-9934-fcbfe3f65eb1

tenancy.yaml

@@ -8,6 +8,27 @@ framework: netkingdom-tenancy-posture
 service: flex-auth
 role: policy-decision-point
 
+workload_identity:
+  name: flex-auth
+  kind: platform-service
+  responsible_repo: flex-auth
+  identity_bindings:
+    - scheme: kubernetes-service-account
+      authority: railiance01
+      subject: system:serviceaccount:flex-auth:flex-auth-ops-warden
+      principal_type: service
+      environment: prod
+    - scheme: kubernetes-service-account
+      authority: railiance01
+      subject: system:serviceaccount:flex-auth:flex-auth-user-engine
+      principal_type: service
+      environment: prod
+    - scheme: kubernetes-service-account
+      authority: railiance01
+      subject: system:serviceaccount:flex-auth:flex-auth-tenant-engine
+      principal_type: service
+      environment: prod
+
 tenancy:
   current:
     I: 1
@@ -77,6 +98,26 @@ provider:
       evidence:
         - "docs/tenancy-posture-review.md"
 
+zones:
+  standard: security-zones_v0.1
+  membership: z1-operational
+  responsible_party: team:platform-security
+  justification: >-
+    Three isolated production policy pins have a bounded platform scope and
+    internal authorization metadata exposure. M1 is evidenced; absent SLO
+    history, on-call, and incident exercises, z2-protected would overclaim.
+  context:
+    maturity: M1
+    criticality: medium
+    data_classification: internal
+  evidence:
+    - ref: docs/evidence/security-zone-admission-2026-08-22.md
+      supports: [M1, platform-only-scope, basic-slo, data-handling-note]
+    - ref: docs/ops-warden-registry-sync.md
+      supports: [production-runbook, decision-observability]
+  reviewed: "2026-08-22"
+  review_due: "2026-11-22"
+
 evidence:
   E1:
     - "internal/decision/engine.go:188"