Add a Grafana dashboard for the resolver's metrics

With traffic charts gone from the console, deploy/grafana/fancy-dns.json is
where they live: queries by outcome, transport and client group, latency
quantiles, RCODEs, cache hits/misses/stale, the upstream round trips saved by
coalescing and early refresh, upstream health and latency, blocklist and zone
sizes, and (in a Loki row) the blocked/failed-query access log. A node variable
spreads or narrows every panel, and the per-node panel shows whether load is
even across pods.

A test reads the dashboard and fails if a panel queries a metric the resolver
does not export, so a rename cannot silently empty a panel.

The ingress no longer needs the SSE buffering/timeout annotations, and the
statefulset comments no longer describe a query log on the volume.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

deploy/k8s/30-ingress.yaml

@@ -13,13 +13,6 @@ metadata:
     k8s-helper.io/icon: "network"
     nginx.ingress.kubernetes.io/backend-protocol: "HTTP"
     cert-manager.io/cluster-issuer: letsencrypt-prod
-    # SSE (the live query log) is the reason for these three. With response
-    # buffering on, nginx holds events until the buffer fills and the log page
-    # looks frozen; with a 60s read timeout the stream is cut every minute and
-    # the page reconnects in a loop.
-    nginx.ingress.kubernetes.io/proxy-buffering: "off"
-    nginx.ingress.kubernetes.io/proxy-read-timeout: "3600"
-    nginx.ingress.kubernetes.io/proxy-send-timeout: "3600"
 spec:
   ingressClassName: nginx
   rules: