Implement inbound caller authentication (ADR 0004); close T03 and T05

TokenReview-based caller identity with audience-scoped tokens and exact
resource.system to ServiceAccount bindings, per ops-warden's recommendation.
Deletes the unwired tenant-engine live-roles adapter (T03) and adds
make verify-posture (T05). Source implements A2; running digest is still A0
until promotion, so tenancy.current.A stays 0.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

tenancy.yaml

@@ -1,8 +1,10 @@
 # flex-auth tenancy posture declaration
-# Framework: net-kingdom/canon/standards/tenancy-posture_v0.1.md (§5)
+# Framework: net-kingdom/canon/standards/tenancy-posture_v0.1.md draft-8 (§5)
 # Conformance rule (§6): accuracy, not altitude. This file overclaims nothing.
 # Reasoning and evidence: docs/tenancy-posture-review.md
 
+schema_version: "0.1"
+framework: netkingdom-tenancy-posture
 service: flex-auth
 role: policy-decision-point
 
@@ -10,22 +12,24 @@ tenancy:
   current:
     I: 1
     A: 0
-    E: 2
+    E: 1
     P: "n/a"
     R: "n/a"
+    V: 0
+  implemented:
+    A: 2
+    E: 2
   target:
     I: 1
     A: 2
     E: 2
     P: "n/a"
     R: "n/a"
-  reviewed: "2026-08-17"
+    V: 1
+  reviewed: "2026-08-18"
+  review_due: "2027-02-17"
   service_class: latency-critical
-
-  # flex-auth is the PDP, not a PEP. The A ladder as written describes
-  # enforcement points delegating outward; flex-auth is the thing delegated to.
-  # Two numbers are therefore needed and only one has a slot (see review §3.1).
-  enables_for_consumers: 3
+  permanent: [I, P, R]
 
   gap:
     I: >-
@@ -35,17 +39,17 @@ tenancy:
       decision point judges asserted claims, it cannot be the verifier of its
       own inputs. Not a defect and not a target for movement.
     A: >-
-      POST /v1/check and /v1/batch_check authenticate no caller. Any workload
-      with network reach to the ClusterIP Service can assert any subject and
-      any tenant and receive an authoritative decision. Mitigated only by
-      cluster-internal exposure. Target A2 (single inbound choke point binding
-      caller identity) under FLEX-WP-0015-T02.
+      The running immutable digest still authenticates no caller, so current
+      remains A0. Source and reviewed desired manifests implement A2 with an
+      audience-scoped Kubernetes TokenReview choke point and exact
+      protected-system-to-ServiceAccount bindings. Promotion and a live
+      unbound-request probe remain under FLEX-WP-0011/FLEX-WP-0015-T02.
     E: >-
       No tenant data at rest. Tenant scoping in decisions runs through one
       choke point (internal/decision/engine.go normalizeRequest and the
       relationship tenant match). E2 evidence is adversarial per §13.2 and is
-      not yet produced; the claim rests on code review only, which §13
-      does not accept. Treat E2 as asserted-pending-evidence.
+      not yet produced. Draft-8 distinguishes implemented from evidenced, so
+      current remains E1 until that review exists.
     P: >-
       No rung applies. flex-auth holds no datastore: registry snapshot and
       policy package are baked into the image and mounted read-only, and the
@@ -55,8 +59,31 @@ tenancy:
       No rung applies, same reason. No tenant data is persisted in production,
       so there is nothing to retain or erase. R0 ("kept indefinitely by
       default") would misdescribe a service that keeps nothing.
+    V: >-
+      No restart or failover exercise establishes an availability position for
+      the complete decision path. The target is exercised V1 recovery, not an
+      inferred claim from a Deployment manifest.
+
+provider:
+  capability: authorization.decision
+  axes:
+    A:
+      available: 3
+      maximum: 4
+      conditions:
+        - "A3 consumers authenticate flex-auth and observe a denial at their endpoint."
+        - "A4 requires the AuthZEN interface and records decision differences between PDPs."
+      evidence:
+        - "docs/tenancy-posture-review.md"
 
 evidence:
-  A: "None. A0 is a declared absence, not a claim; see review §3.5 on low-rung evidence."
-  E2: "Pending adversarial artifact. Code choke point: internal/decision/engine.go:188,248"
+  E1:
+    - "internal/decision/engine.go:188"
+    - "internal/decision/engine.go:248"
+  A2:
+    - "internal/callerauth/auth.go"
+    - "internal/callerauth/auth_test.go"
+    - "cmd/flex-auth/main_test.go"
+    - "deploy/caller-auth-rbac.yaml"
+    - "docs/adr/0004-inbound-caller-authentication.md"
   deployment: "deploy/flex-auth-user-engine.yaml, deploy/flex-auth-tenant-engine.yaml"