Add k8s.container.ready to md (#2308)

Signed-off-by: ChrsMark <chrismarkou92@gmail.com>

docs/system/k8s-metrics.md

@@ -78,6 +78,7 @@ and therefore inherit its attributes, like `k8s.pod.name` and `k8s.pod.uid`.
   - [Metric: `k8s.container.ephemeral_storage.limit`](#metric-k8scontainerephemeral_storagelimit)
   - [Metric: `k8s.container.ephemeral_storage.request`](#metric-k8scontainerephemeral_storagerequest)
   - [Metric: `k8s.container.restart.count`](#metric-k8scontainerrestartcount)
+  - [Metric: `k8s.container.ready`](#metric-k8scontainerready)
 
 <!-- tocstop -->
 
@@ -1392,5 +1393,28 @@ you can conclude there were restarts in the recent past, and not try and analyze
 <!-- END AUTOGENERATED TEXT -->
 <!-- endsemconv -->
 
+### Metric: `k8s.container.ready`
+
+This metric is [recommended][MetricRecommended].
+
+<!-- semconv metric.k8s.container.ready -->
+<!-- NOTE: THIS TEXT IS AUTOGENERATED. DO NOT EDIT BY HAND. -->
+<!-- see templates/registry/markdown/snippet.md.j2 -->
+<!-- prettier-ignore-start -->
+<!-- markdownlint-capture -->
+<!-- markdownlint-disable -->
+
+| Name     | Instrument Type | Unit (UCUM) | Description    | Stability | Entity Associations |
+| -------- | --------------- | ----------- | -------------- | --------- | ------ |
+| `k8s.container.ready` | UpDownCounter | `{container}` | Indicates whether the container is currently marked as ready to accept traffic, based on its readiness probe (1 = ready, 0 = not ready) [1] | ![Development](https://img.shields.io/badge/-development-blue) | `k8s.container` |
+
+**[1]:** This metric SHOULD reflect the value of the `ready` field in the
+[K8s ContainerStatus](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.30/#containerstatus-v1-core).
+
+<!-- markdownlint-restore -->
+<!-- prettier-ignore-end -->
+<!-- END AUTOGENERATED TEXT -->
+<!-- endsemconv -->
+
 [DocumentStatus]: https://opentelemetry.io/docs/specs/otel/document-status
 [MetricRecommended]: /docs/general/metric-requirement-level.md#recommended