feat(infra): production bootstrap — cert-manager, longhorn, monitoring

Add new bases for cert-manager (Let's Encrypt + wildcard cert), Longhorn
distributed storage, and monitoring (kube-prometheus-stack + Loki + Tempo
+ Grafana OIDC). Add cloud-init for Scaleway Elastic Metal provisioning.

Production overlay: add patches for postgres sizing, SeaweedFS volume,
OpenSearch storage, LiveKit service, Pingora host ports, resource limits,
and CNPG daily barman backups. Update cert-manager.yaml with full dnsNames
for all *.sunbeam.pt subdomains.

overlays/production/patch-opensearch-storage.yaml

@@ -0,0 +1,10 @@
+# Expand OpenSearch PVC to 50 Gi in production.
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: opensearch-data
+  namespace: data
+spec:
+  resources:
+    requests:
+      storage: 50Gi