phase2-prep: per-component no-secret rollout + component hardening (author-first)

Prep only — nothing deployed; running cluster untouched.

Reconciliation graph (operator-approved Option A): author clusters/dev/rollout/
= 4 per-component Flux Kustomizations (kyverno->cilium->longhorn->monitoring,
monitoring dependsOn longhorn). Dev overlay $patch:delete's the monolithic base
platform/apps and adds ./rollout, so only the no-secret tier reconciles; the
secret-blocked components are simply not created until hand-offs arrive. The
no-secret tier carries no SOPS content, so it needs no sops-age key. prod is
untouched (still builds the monolith). Convergence path coded in (delete rollout/
+ the two deletes) — R-ENV-02 divergence flagged for architect review.

Component hardening via cluster-vars (prod keeps strict posture):
- KYVERNO_VALIDATION_ACTION Enforce->Audit(dev), _WEBHOOK_FAILURE_POLICY
  Fail->Ignore(dev), _ADMISSION_REPLICAS 3->1(dev); webhook namespaceSelector
  excludes system+platform namespaces.
- MONITORING_STORAGE_CLASS var; GRAFANA_ADMIN_SECRET var (dev ''=chart default);
  Alertmanager SMTP/secret deferred to Phase-4 with verbatim re-enable markers.

Cilium parity verified against the live CNI (no-op adopt). Validated:
kubectl kustomize dev/prod/all-components, envsubst->YAML parse, make -C ci gate PASS.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

platform/monitoring/loki.yaml

@@ -60,7 +60,7 @@ spec:
       replicas: 1
       persistence:
         enabled: true
-        storageClass: longhorn          # replicated tier (ADR-0003)
+        storageClass: ${MONITORING_STORAGE_CLASS}   # replicated tier (ADR-0003); cluster-vars knob
         size: ${MONITORING_LOKI_PVC_SIZE}   # overlay knob (dev 5Gi / prod large)
       resources:
         requests: