feat(ci): GitLab CI/CD dev→prod pipeline, kustomize base+overlays

Multiple developers now work on this repo, and the only working deploy
trigger required pushing to GitHub - which contradicts the standing
GitLab-canonical policy for this repo - while every actual deploy was a
manual kubectl run against one environment (no prod exists at all).

Restructures deploy/k8s/ into base/ + overlays/{dev,prod}: overlays/dev
is a verified byte-for-byte no-op for the live sandbox (kubectl kustomize
diff against the old flat layout is empty), overlays/prod is scaffolded
but inert (placeholder hostname + JMAP_SERVER_URL, since neither a prod
hostname decision nor a prod Stalwart exist yet). deploy/k8s/ca/ (the
EJBCA internal CA) is untouched and never referenced by either overlay.

Adds .gitlab-ci.yml: verify (MR gate, no push/deploy) -> build+deploy-dev
(automatic on push to dev, one image name/tag-only environments, fixing
the old -dev/-beta naming split) -> promote (manual, protected
`production` environment, retags the exact dev digest via
`docker buildx imagetools create` - never rebuilds - and is left as a
documented TODO for the actual `kubectl apply` until prod is real).

Updates VNCMAIL-SETUP.md and deploy/k8s/README.md to describe the new
flow and correct the aspirational promotion description that assumed a
"production image" CI never actually built.

Also fixes a pre-existing lint error (no-control-regex false positive on
an intentional DN-sanitizing character class in lib/smime-ca/ejbca.ts)
that was blocking this commit's pre-commit hook - unrelated to this
change otherwise, confirmed already present on dev before this branch.

Runner/RBAC/registry setup is an infra prerequisite this commit cannot
provide - documented in the pipeline plan, not part of this diff.

deploy/k8s/base/deployment.yaml

@@ -0,0 +1,91 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: vncmail-plus
+  labels:
+    app: vncmail-plus
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: vncmail-plus
+  # RWO volumes can only mount to one pod — Recreate avoids a stuck rollout.
+  strategy:
+    type: Recreate
+  template:
+    metadata:
+      labels:
+        app: vncmail-plus
+    spec:
+      # The image runs as uid/gid 1001 (nextjs:nodejs) and the Dockerfile
+      # chowns /app/data to 1001. fsGroup makes the mounted PVCs writable by it.
+      securityContext:
+        fsGroup: 1001
+        runAsUser: 1001
+        runAsGroup: 1001
+      # ghcr package is private by default — see deploy/k8s/README.md to create
+      # this pull secret. Delete this block if you make the package public.
+      # NOTE: once CI moves to pushing registry.gitlab.vnc.biz images (the
+      # dev-auto-deploy phase of the GitLab pipeline), this needs to become a
+      # docker-registry secret for that registry instead — comments only,
+      # deliberately not renamed here, so this file stays a no-op today.
+      imagePullSecrets:
+        - name: ghcr-pull
+      containers:
+        - name: vncmail-plus
+          # Default/legacy value — CI overrides the image per-deploy via
+          # `kustomize edit set image`, so what's committed here never goes
+          # stale. For a one-off manual apply, pin a digest instead of :latest.
+          image: ghcr.io/brvncde-dotcom/vncmail-plus-dev:latest
+          imagePullPolicy: Always
+          ports:
+            - containerPort: 3000
+          envFrom:
+            - secretRef:
+                name: vncmail-env
+          env:
+            - name: HOSTNAME
+              value: "0.0.0.0"
+            - name: PORT
+              value: "3000"
+          readinessProbe:
+            httpGet:
+              path: /api/health
+              port: 3000
+            initialDelaySeconds: 10
+            periodSeconds: 10
+          livenessProbe:
+            httpGet:
+              path: /api/health
+              port: 3000
+            initialDelaySeconds: 25
+            periodSeconds: 30
+          resources:
+            requests:
+              cpu: 100m
+              memory: 256Mi
+            limits:
+              cpu: "1"
+              memory: 1Gi
+          volumeMounts:
+            - name: settings
+              mountPath: /app/data/settings
+            - name: admin
+              mountPath: /app/data/admin
+            - name: admin-state
+              mountPath: /app/data/admin-state
+            - name: telemetry
+              mountPath: /app/data/telemetry
+      volumes:
+        - name: settings
+          persistentVolumeClaim:
+            claimName: vncmail-settings
+        - name: admin
+          persistentVolumeClaim:
+            claimName: vncmail-admin
+        - name: admin-state
+          persistentVolumeClaim:
+            claimName: vncmail-admin-state
+        - name: telemetry
+          persistentVolumeClaim:
+            claimName: vncmail-telemetry

deploy/k8s/base/ingress.yaml

@@ -0,0 +1,33 @@
+# Exposes VNCmail+ at vncmail.sandbox.vnc.de, alongside bulwark.sandbox.vnc.de.
+# MATCH YOUR CLUSTER — inspect the existing Bulwark ingress and copy its
+# ingressClassName + TLS/cert-manager annotations:
+#   kubectl get ingress -A | grep bulwark
+#   kubectl get ingress <bulwark-ingress> -n <ns> -o yaml
+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  name: vncmail-plus
+  annotations:
+    # cert-manager issuer — set to whatever bulwark.sandbox.vnc.de uses.
+    cert-manager.io/cluster-issuer: letsencrypt-prod
+    # Mail attachments can be large; raise the nginx body limit.
+    nginx.ingress.kubernetes.io/proxy-body-size: "100m"
+spec:
+  # microk8s ingress addon class is usually "public" (nginx). Confirm with
+  # `kubectl get ingressclass` and match bulwark's.
+  ingressClassName: public
+  tls:
+    - hosts:
+        - vncmail.sandbox.vnc.de
+      secretName: vncmail-plus-tls
+  rules:
+    - host: vncmail.sandbox.vnc.de
+      http:
+        paths:
+          - path: /
+            pathType: Prefix
+            backend:
+              service:
+                name: vncmail-plus
+                port:
+                  number: 80

deploy/k8s/base/kustomization.yaml

@@ -0,0 +1,14 @@
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+resources:
+  - pvc.yaml
+  - deployment.yaml
+  - service.yaml
+  - ingress.yaml
+  # - secret.yaml   # create from an overlay's secret.example.yaml; not committed
+
+# Namespace is intentionally NOT set here. Kustomize's `namespace:` transformer
+# doesn't rename cluster-scoped Namespace objects, so each overlay ships its own
+# namespace.yaml (the actual object) and its own `namespace:` field (which
+# injects metadata.namespace into every namespaced resource below). Applying
+# this base directly is meaningless — always go through an overlay.

deploy/k8s/base/pvc.yaml

@@ -0,0 +1,46 @@
+# Four persistent volumes — mirror the fork's docker-compose volumes.
+# storageClassName: microk8s default is "microk8s-hostpath". Match your
+# cluster: `kubectl get sc`. Change all four if yours differs.
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: vncmail-settings
+spec:
+  accessModes: [ReadWriteOnce]
+  storageClassName: microk8s-hostpath
+  resources:
+    requests:
+      storage: 1Gi
+---
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: vncmail-admin
+spec:
+  accessModes: [ReadWriteOnce]
+  storageClassName: microk8s-hostpath
+  resources:
+    requests:
+      storage: 256Mi
+---
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: vncmail-admin-state
+spec:
+  accessModes: [ReadWriteOnce]
+  storageClassName: microk8s-hostpath
+  resources:
+    requests:
+      storage: 256Mi
+---
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: vncmail-telemetry
+spec:
+  accessModes: [ReadWriteOnce]
+  storageClassName: microk8s-hostpath
+  resources:
+    requests:
+      storage: 256Mi

deploy/k8s/base/service.yaml

@@ -0,0 +1,13 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: vncmail-plus
+  labels:
+    app: vncmail-plus
+spec:
+  selector:
+    app: vncmail-plus
+  ports:
+    - name: http
+      port: 80
+      targetPort: 3000