samosaChaat observability stack installed.

Components:
  * kube-prometheus-stack  -> Prometheus, Alertmanager, Grafana, node-exporter, kube-state-metrics
  * loki-stack             -> Loki (logs) + Promtail (log shipping)

Access:
  Grafana is exposed at https://grafana.samosachaat.art via the samosaChaat
  app-chart ingress. Login is OAuth-only (GitHub + Google); the local login form
  is disabled.

Required secrets in namespace {{ .Release.Namespace }}:
  kubectl create secret generic grafana-oauth-secrets \
    --from-literal=GITHUB_GRAFANA_CLIENT_ID=... \
    --from-literal=GITHUB_GRAFANA_CLIENT_SECRET=... \
    --from-literal=GOOGLE_GRAFANA_CLIENT_ID=... \
    --from-literal=GOOGLE_GRAFANA_CLIENT_SECRET=... \
    --from-literal=SLACK_WEBHOOK_URL=...

Useful in-cluster URLs:
  Prometheus: http://prom-kube-prometheus-stack-prometheus.{{ .Release.Namespace }}.svc:9090
  Loki:       http://loki.{{ .Release.Namespace }}.svc:3100