[ci skip] Infrastructure hardening: security, monitoring, reliability, maintainability

Phase 1 - Critical Security:
- Netbox: move hardcoded DB/superuser passwords to variables
- MeshCentral: disable public registration, add Authentik auth
- Traefik: disable insecure API dashboard (api.insecure=false)
- Traefik: configure forwarded headers with Cloudflare trusted IPs

Phase 2 - Security Hardening:
- Add security headers middleware (HSTS, X-Frame-Options, nosniff, etc.)
- Add Kyverno pod security policies in audit mode (privileged, host
  namespaces, SYS_ADMIN, trusted registries)
- Tighten rate limiting (avg=10, burst=50)
- Add Authentik protection to grampsweb

Phase 3 - Monitoring & Alerting:
- Add critical service alerts (PostgreSQL, MySQL, Redis, Headscale,
  Authentik, Loki)
- Increase Loki retention from 7 to 30 days (720h)
- Add predictive PV filling alert (predict_linear)
- Re-enable Hackmd and Privatebin down alerts

Phase 4 - Reliability:
- Add resource requests/limits to Redis, DBaaS, Technitium, Headscale,
  Vaultwarden, Uptime Kuma
- Increase Alloy DaemonSet memory to 512Mi/1Gi

Phase 6 - Maintainability:
- Extract duplicated tiers locals to terragrunt.hcl generate block
  (removed from 67 stacks)
- Replace hardcoded NFS IP 10.0.10.15 with var.nfs_server (114
  instances across 63 files)
- Replace hardcoded Redis/PostgreSQL/MySQL/Ollama/mail host references
  with variables across ~35 stacks
- Migrate xray raw ingress resources to ingress_factory modules

stacks/platform/modules/technitium/main.tf

@@ -2,6 +2,8 @@ variable "tls_secret_name" {}
 variable "tier" { type = string }
 variable "homepage_token" {}
 variable "technitium_db_password" {}
+variable "nfs_server" { type = string }
+variable "mysql_host" { type = string }
 
 resource "kubernetes_namespace" "technitium" {
   metadata {
@@ -131,14 +133,14 @@ resource "kubernetes_deployment" "technitium" {
           image = "technitium/dns-server:latest"
           name  = "technitium"
           resources {
-            # limits = {
-            #   cpu    = "1"
-            #   memory = "1Gi"
-            # }
-            # requests = {
-            #   cpu    = "1"
-            #   memory = "1Gi"
-            # }
+            requests = {
+              cpu    = "100m"
+              memory = "128Mi"
+            }
+            limits = {
+              cpu    = "500m"
+              memory = "512Mi"
+            }
           }
           port {
             container_port = 5380
@@ -162,7 +164,7 @@ resource "kubernetes_deployment" "technitium" {
           name = "nfs-config"
           nfs {
             path   = "/mnt/main/technitium"
-            server = "10.0.10.15"
+            server = var.nfs_server
           }
         }
         volume {
@@ -278,7 +280,7 @@ resource "kubernetes_config_map" "grafana_technitium_datasource" {
         name     = "Technitium MySQL"
         type     = "mysql"
         access   = "proxy"
-        url      = "mysql.dbaas.svc.cluster.local:3306"
+        url      = "${var.mysql_host}:3306"
         database = "technitium"
         user     = "technitium"
         uid      = "technitium-mysql"