Add Kubernetes manifests for car.stinnesbeck.com

Namespace, InfluxDB 2.7.12 StatefulSet with PVC and a NetworkPolicy
that admits only the server, the server Deployment (non-root, read-only
root filesystem), a cert-manager Certificate from letsencrypt-prod and a
Traefik IngressRoute. Secrets are a template only. Nothing is applied;
k8s/README.md has the steps. Server version bumped to 1.1.0.

Validated offline with kustomize and kubeconform (including the
cert-manager and Traefik CRD schemas). The InfluxDB container was tested
locally as UID 1000 with no capabilities.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

k8s/influxdb.yaml

@@ -0,0 +1,130 @@
+# InfluxDB 2, cluster-internal only. On first start (empty volume) the image's setup mode
+# creates the org, the bucket and the admin token from the influxdb-auth Secret; on later
+# starts those variables are ignored and the data on the volume wins.
+apiVersion: apps/v1
+kind: StatefulSet
+metadata:
+  name: influxdb
+  namespace: mg4
+  labels:
+    app.kubernetes.io/name: influxdb
+    app.kubernetes.io/part-of: mg4
+spec:
+  serviceName: influxdb
+  replicas: 1
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: influxdb
+  template:
+    metadata:
+      labels:
+        app.kubernetes.io/name: influxdb
+        app.kubernetes.io/part-of: mg4
+    spec:
+      securityContext:
+        runAsNonRoot: true
+        runAsUser: 1000
+        runAsGroup: 1000
+        fsGroup: 1000
+        seccompProfile:
+          type: RuntimeDefault
+      containers:
+        - name: influxdb
+          image: docker.io/library/influxdb:2.7.12-alpine
+          ports:
+            - name: http
+              containerPort: 8086
+          env:
+            - name: INFLUXD_REPORTING_DISABLED
+              value: "true"
+            - name: DOCKER_INFLUXDB_INIT_MODE
+              value: setup
+            - name: DOCKER_INFLUXDB_INIT_ORG
+              value: mg4
+            - name: DOCKER_INFLUXDB_INIT_BUCKET
+              value: mg4
+            - name: DOCKER_INFLUXDB_INIT_USERNAME
+              value: admin
+            - name: DOCKER_INFLUXDB_INIT_PASSWORD
+              valueFrom:
+                secretKeyRef:
+                  name: influxdb-auth
+                  key: admin-password
+            - name: DOCKER_INFLUXDB_INIT_ADMIN_TOKEN
+              valueFrom:
+                secretKeyRef:
+                  name: influxdb-auth
+                  key: admin-token
+          volumeMounts:
+            - name: data
+              mountPath: /var/lib/influxdb2
+            - name: config
+              mountPath: /etc/influxdb2
+          readinessProbe:
+            httpGet:
+              path: /health
+              port: http
+            periodSeconds: 10
+          livenessProbe:
+            httpGet:
+              path: /health
+              port: http
+            initialDelaySeconds: 30
+            periodSeconds: 30
+          resources:
+            requests:
+              cpu: 100m
+              memory: 256Mi
+            limits:
+              memory: 1Gi
+          securityContext:
+            allowPrivilegeEscalation: false
+            capabilities:
+              drop: ["ALL"]
+      volumes:
+        - name: config
+          emptyDir: {}
+  volumeClaimTemplates:
+    - metadata:
+        name: data
+      spec:
+        accessModes: ["ReadWriteOnce"]
+        # No storageClassName: the cluster's default class is used.
+        resources:
+          requests:
+            storage: 10Gi
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: influxdb
+  namespace: mg4
+  labels:
+    app.kubernetes.io/name: influxdb
+    app.kubernetes.io/part-of: mg4
+spec:
+  selector:
+    app.kubernetes.io/name: influxdb
+  ports:
+    - name: http
+      port: 8086
+      targetPort: http
+---
+# Only the server may reach InfluxDB. Has no effect on a CNI without NetworkPolicy support.
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: influxdb-from-server-only
+  namespace: mg4
+spec:
+  podSelector:
+    matchLabels:
+      app.kubernetes.io/name: influxdb
+  policyTypes: ["Ingress"]
+  ingress:
+    - from:
+        - podSelector:
+            matchLabels:
+              app.kubernetes.io/name: mg4-server
+      ports:
+        - port: 8086