feat(k8s): add K8s manifests for all homelab services

traefik, gitea, adguard, nextcloud, errorpages, homepages,
uptime-kuma, kener, checkmk, headscale, dockmon, metube,
downtify, portainer, netronome, userbot

Includes Helm values, deployments, services, ingress routes,
configmaps, secrets (placeholders), postgres statefulsets,
kustomize overlays, and Traefik dynamic configuration.

errorpages/k8s/error-pages.yaml

@@ -0,0 +1,34 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: error-pages-service
+  namespace: error-pages
+spec:
+  selector:
+    app: error-pages
+  ports:
+  - port: 80
+    targetPort: 80
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: error-pages-deployment
+  namespace: error-pages
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: error-pages
+  template:
+    metadata:
+      labels:
+        app: error-pages
+    spec:
+      containers:
+      - name: error-pages
+        image: gcr.forust.xyz/forust/error-pages:latest
+        ports:
+        - containerPort: 80
+---
+

errorpages/k8s/namespace.yaml

@@ -0,0 +1,4 @@
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: error-pages