Enable Grafana Argo self-healing and pruning

apps/grafana/README.md

@@ -0,0 +1,11 @@
+# Grafana cluster deployment
+
+Argo CD owns the Grafana Helm release and the dashboard ConfigMaps in
+`resources/`. The selected upstream chart version is recorded once in
+`bootstrap/grafana.yaml`; change it there to upgrade.
+
+The existing `grafana` Secret supplies the admin credentials, while
+`grafana-postgres-secret` supplies database and OAuth credentials. They are
+referenced by name and must remain cluster-managed; do not add their data to
+this public repository. The prior Helm release record is retained for recovery
+and must not be upgraded or uninstalled after Argo adoption.

bootstrap/grafana.yaml

@@ -25,5 +25,5 @@ spec:
   syncPolicy:
     automated:
       enabled: true
-      prune: false
-      selfHeal: false
+      prune: true
+      selfHeal: true