T-0.1 Flux GitOps layout + dev/prod overlays + platform component skeletons (R-GITOPS-01/03, R-ENV-02, R-PLAT-01)

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

platform/longhorn/helmrelease.yaml

@@ -0,0 +1,36 @@
+---
+# Longhorn — distributed replicated block storage (ADR-0003). Phase 0 STUB.
+apiVersion: helm.toolkit.fluxcd.io/v2
+kind: HelmRelease
+metadata:
+  name: longhorn
+  namespace: longhorn-system
+spec:
+  interval: 30m
+  chart:
+    spec:
+      chart: longhorn
+      version: ">=1.7.0 <1.8.0"   # TODO(WS-STORAGE): pin at bring-up; Renovate maintains
+      sourceRef:
+        kind: HelmRepository
+        name: longhorn
+        namespace: longhorn-system
+  install:
+    createNamespace: false
+    remediation:
+      retries: 3
+  upgrade:
+    remediation:
+      retries: 3
+  values:
+    # We define StorageClasses ourselves (storageclasses.yaml) so the default 3-replica SC and the
+    # bulk tier are explicit and GitOps-managed. Disable the chart's built-in default SC.
+    persistence:
+      defaultClass: false
+      # ${LONGHORN_DEFAULT_REPLICA_COUNT} resolved from cluster-vars (R-ENV-02).
+      defaultClassReplicaCount: ${LONGHORN_DEFAULT_REPLICA_COUNT}
+    defaultSettings:
+      # TODO(WS-STORAGE, Phase 2): set defaultDataPath to the dedicated Longhorn data disk
+      #   (docs/02 — a dedicated data disk is presented to Longhorn on each node).
+      defaultDataPath: "/var/lib/longhorn"
+    # TODO(WS-STORAGE, Phase 4): configure off-cluster backup target here (see velero/ + ADR-0003).