Catalyst Blueprint umbrella for Grafana — visualization layer of the
LGTM observability stack (Loki/Grafana/Tempo/Mimir).
Pinned to grafana/grafana 10.5.15 (appVersion 12.3.1) — current stable
on 2026-04-29. Solo-Sovereign defaults: 1 replica, 10Gi PVC,
ServiceMonitor disabled per BLUEPRINT-AUTHORING.md §11.2.
Part of issue #204 observability-stack umbrellas batch.