docs (k8s): Add Prometheus ServiceMonitor section for Console on K8s

modules/deploy/pages/console/kubernetes/deploy.adoc

@@ -390,6 +390,8 @@ spec:
 
 == Monitoring
 
+Configure metrics exposure and Prometheus scraping for Redpanda Console.
+
 Enable monitoring for Redpanda Console:
 
 [,yaml]
@@ -401,6 +403,88 @@ config:
       port: 9090
 ----
 
+=== Prometheus ServiceMonitor
+
+If you use the https://github.com/prometheus-operator/prometheus-operator[Prometheus Operator^], deploy a `ServiceMonitor` resource alongside Redpanda Console. Prometheus then discovers and scrapes Console metrics from the `/admin/metrics` endpoint.
+
+[tabs]
+======
+Operator::
++
+--
+
+To enable the ServiceMonitor in the Console custom resource, set `monitoring.enabled` to `true`:
+
+[,yaml]
+----
+apiVersion: cluster.redpanda.com/v1alpha2
+kind: Console
+metadata:
+  name: redpanda-console
+  namespace: redpanda
+spec:
+  monitoring:
+    enabled: true <1>
+    scrapeInterval: "30s" <2>
+    labels: <3>
+      release: kube-prometheus-stack
+  cluster:
+    clusterRef:
+      name: redpanda
+----
+
+<1> Set to `true` to create a `ServiceMonitor` resource. Default: `false`.
+<2> How often Prometheus scrapes the metrics endpoint. Default: `1m`.
+<3> Additional labels to apply to the `ServiceMonitor`. Match your Prometheus Operator's `serviceMonitorSelector` by applying the same labels here.
+
+Apply the Console CR:
+
+[,bash]
+----
+kubectl apply -f console.yaml --namespace redpanda
+----
+
+--
+Helm::
++
+--
+
+To enable the ServiceMonitor in the Console Helm chart, add the following to your `console-values.yaml`:
+
+[,yaml]
+----
+monitoring:
+  enabled: true <1>
+  scrapeInterval: "30s" <2>
+  labels: {} <3>
+----
+
+<1> Set to `true` to create a `ServiceMonitor` resource. Default: `false`.
+<2> How often Prometheus scrapes the metrics endpoint. Default: `1m`.
+<3> Additional labels to apply to the `ServiceMonitor`. Match your Prometheus Operator's `serviceMonitorSelector` by applying the same labels here. For example:
++
+[,yaml]
+----
+monitoring:
+  enabled: true
+  labels:
+    release: kube-prometheus-stack
+----
+
+If you deploy Redpanda Console as a subchart of the Redpanda Helm chart, configure monitoring under the `console` key. All `monitoring` options are available under this key.
+
+[,yaml]
+----
+console:
+  monitoring:
+    enabled: true
+----
+
+--
+======
+
+When the Console server is configured with TLS (`config.server.tls.enabled: true`), the ServiceMonitor uses HTTPS and configures CA validation for scraping.
+
 == Troubleshooting
 
 * **Connection refused**: Verify Redpanda broker addresses and network policies