extract remaining 19 modules from platform, complete stack split [ci skip]

Phase 3: all 27 platform modules now run as independent stacks.
Platform reduced to empty shell (outputs only) for backward compat
with 72 app stacks that declare dependency "platform".
Fixed technitium cross-module dashboard reference by copying file.
Woodpecker pipeline applies all 27+1 stacks in parallel via loop.
All applied with zero destroys.

stacks/cnpg/modules/cnpg/main.tf

@@ -0,0 +1,53 @@
+variable "tier" { type = string }
+
+# -----------------------------------------------------------------------------
+# Namespace
+# -----------------------------------------------------------------------------
+resource "kubernetes_namespace" "cnpg_system" {
+  metadata {
+    name = "cnpg-system"
+    labels = {
+      tier = var.tier
+    }
+  }
+}
+
+# -----------------------------------------------------------------------------
+# CloudNativePG Operator — manages PostgreSQL clusters via CRDs
+# https://cloudnative-pg.io/
+# -----------------------------------------------------------------------------
+resource "helm_release" "cnpg" {
+  namespace        = kubernetes_namespace.cnpg_system.metadata[0].name
+  create_namespace = false
+  name             = "cnpg"
+  atomic           = true
+  timeout          = 300
+
+  repository = "https://cloudnative-pg.github.io/charts"
+  chart      = "cloudnative-pg"
+  version    = "0.27.1"
+
+  values = [yamlencode({
+    crds = {
+      create = true
+    }
+
+    replicaCount = 1
+
+    resources = {
+      requests = {
+        cpu    = "100m"
+        memory = "256Mi"
+      }
+      limits = {
+        memory = "256Mi"
+      }
+    }
+  })]
+}
+
+# NOTE: local-path-provisioner is already installed in the cluster
+# (via cloud-init template) with StorageClass "local-path" (default).
+# ReclaimPolicy is "Delete" — for CNPG clusters, set
+# .spec.storage.pvcTemplate.storageClassName = "local-path" in the
+# Cluster CR. CNPG handles PVC lifecycle independently.