k8s/monitoring: add prometheus grafana loki observability

- Loki log aggregation (MinIO backed, 10-day retention)
- Promtail daemonset (pod + talos journal logs)
- Prometheus + kube-state-metrics
- Grafana dashboards (6-row template per service)

k8s/logging/minio-values.yaml

@@ -0,0 +1,42 @@
+# logging/minio-values.yaml
+# Official MinIO chart (minio/minio from https://charts.min.io).
+# Single pod with console built-in on port 9001.
+# rootUser and rootPassword are injected via --set at install time from .env.
+
+mode: standalone
+
+rootUser: ""      # injected via --set
+rootPassword: ""  # injected via --set
+
+persistence:
+  enabled: true
+  storageClass: longhorn
+  accessMode: ReadWriteOnce
+  size: 100Gi
+
+resources:
+  requests:
+    cpu: 100m
+    memory: 256Mi
+  limits:
+    cpu: 500m
+    memory: 512Mi
+
+service:
+  type: ClusterIP
+  port: 9000
+
+consoleService:
+  type: ClusterIP
+  port: 9001
+
+# Disable ingress — access via kubectl port-forward
+ingress:
+  enabled: false
+
+consoleIngress:
+  enabled: false
+
+metrics:
+  serviceMonitor:
+    enabled: false