add pvc-autoresizer for automatic PVC expansion before volumes fill up [ci skip]

Deploy topolvm/pvc-autoresizer controller that monitors kubelet_volume_stats
via Prometheus and auto-expands annotated PVCs. Annotated all 9 block-storage
PVCs (proxmox-lvm) with per-PVC thresholds and max limits. Updated PVFillingUp
alert to critical/10m (means auto-expansion failed) and added PVAutoExpanding
info alert at 80%.

stacks/pvc-autoresizer/modules/pvc-autoresizer/main.tf

@@ -0,0 +1,39 @@
+variable "tier" { type = string }
+
+resource "kubernetes_namespace" "pvc_autoresizer" {
+  metadata {
+    name = "pvc-autoresizer"
+    labels = {
+      tier = var.tier
+    }
+  }
+}
+
+resource "helm_release" "pvc_autoresizer" {
+  namespace        = kubernetes_namespace.pvc_autoresizer.metadata[0].name
+  create_namespace = false
+  name             = "pvc-autoresizer"
+  atomic           = true
+  timeout          = 300
+
+  repository = "https://topolvm.github.io/pvc-autoresizer"
+  chart      = "pvc-autoresizer"
+
+  values = [yamlencode({
+    controller = {
+      args = {
+        prometheusURL = "http://prometheus-server.monitoring.svc.cluster.local:80"
+        interval      = "10m"
+      }
+      resources = {
+        requests = {
+          memory = "64Mi"
+          cpu    = "10m"
+        }
+        limits = {
+          memory = "128Mi"
+        }
+      }
+    }
+  })]
+}