Add Kubernetes manifests for Grafana dashboard and Prometheus scraping

ConfigMap with grafana_dashboard label for sidecar auto-discovery,
and ServiceMonitor for kube-prometheus-stack scrape target.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

k8s/servicemonitor.yaml

@@ -0,0 +1,18 @@
+apiVersion: monitoring.coreos.com/v1
+kind: ServiceMonitor
+metadata:
+  name: pokerface
+  namespace: monitoring
+  labels:
+    release: kube-prometheus-stack
+spec:
+  namespaceSelector:
+    matchNames:
+      - pokerface
+  selector:
+    matchLabels:
+      app: pokerface
+  endpoints:
+    - port: http
+      path: /metrics
+      interval: 15s