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.

portainer/k8s/portainer.yaml

@@ -0,0 +1,57 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: portainer-service
+  namespace: portainer
+spec:
+  selector:
+    app: portainer
+  ports:
+  - port: 9000
+    targetPort: 9000
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: portainer-deployment
+  namespace: portainer
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: portainer
+  template:
+    metadata:
+      labels:
+        app: portainer
+    spec:
+      containers:
+      - name: portainer
+        image: portainer/portainer-ce:2.41.0
+        ports:
+        - containerPort: 9000
+        volumeMounts:
+        - name: data
+          mountPath: /data
+        - name: docker-sock
+          mountPath: /var/run/docker.sock
+      volumes:
+      - name: data
+        persistentVolumeClaim:
+          claimName: portainer-data-pvc
+      - name: docker-sock
+        hostPath:
+          path: /var/run/docker.sock
+          type: Socket
+---
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: portainer-data-pvc
+  namespace: portainer
+spec:
+  accessModes:
+  - ReadWriteOnce
+  resources:
+    requests:
+      storage: 2Gi