P7.3: Add Grafana dashboard with 8 core panels and feature-gated rows (plan §10)

dashboards/miroir-overview.json — 50-panel dashboard covering:
- Core: cluster health, request rate, p50/p95/p99 latency, node comparison,
  search overhead, task lag, shard distribution, rebalance activity
- Feature-gated collapsed rows: multi-search (§13.11), anti-entropy (§13.8),
  settings broadcast (§13.5), CDC (§13.13), canary tests (§13.18),
  search UI (§13.21)

Helm chart: dashboards.enabled creates a ConfigMap labeled
grafana_dashboard=1 for sidecar auto-import.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

charts/miroir/templates/miroir-grafana-dashboard.yaml

@@ -0,0 +1,20 @@
+{{/*
+Grafana dashboard ConfigMap — auto-imported by grafana-dashboard sidecar
+when labeled grafana_dashboard=1.
+*/}}
+{{- if .Values.dashboards.enabled }}
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: {{ include "miroir.fullname" . }}-dashboard
+  labels:
+    {{- include "miroir.labels" . | nindent 4 }}
+    grafana_dashboard: "1"
+  {{- with .Values.dashboards.annotations }}
+  annotations:
+    {{- toYaml . | nindent 4 }}
+  {{- end }}
+data:
+  miroir-overview.json: |
+{{ .Files.Get "dashboards/miroir-overview.json" | indent 4 }}
+{{- end }}

charts/miroir/values.schema.json

@@ -108,6 +108,13 @@
         "annotations": { "type": "object" }
       }
     },
+    "dashboards": {
+      "type": "object",
+      "properties": {
+        "enabled": { "type": "boolean" },
+        "annotations": { "type": "object" }
+      }
+    },
     "prometheusRule": {
       "type": "object",
       "properties": {

charts/miroir/values.yaml

@@ -148,6 +148,11 @@ prometheusRule:
   enabled: false  # requires prometheus-operator in cluster
   annotations: {}
 
+# Grafana dashboard ConfigMap (requires grafana-dashboard sidecar)
+dashboards:
+  enabled: false  # creates a ConfigMap labeled grafana_dashboard=1
+  annotations: {}
+
 # OpenTelemetry tracing (plan §10)
 tracing:
   enabled: false  # disabled by default for zero overhead