update WorkerResourceTemplateSpec doc comment: remove template expressions, document metric selector injection

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: carlydf

api/v1alpha1/workerresourcetemplate_types.go

@@ -23,12 +23,22 @@ type WorkerResourceTemplateSpec struct {
 	// Must include apiVersion, kind, and spec. metadata.name and metadata.namespace
 	// are generated by the controller; do not set them.
 	//
-	// String values in the spec may use Go template expressions:
-	//   {{ .K8sNamespace }}, {{ .TWDName }}, {{ .TemporalNamespace }}, {{ .BuildID }}
+	// The controller auto-injects fields when they are present as an empty object ({}):
 	//
-	// The controller auto-injects two well-known fields when present as an empty object:
-	//   scaleTargetRef: {} - injected to point at the versioned Deployment (HPA, WPA, etc.)
-	//   matchLabels: {}    - injected with the versioned Deployment selector labels (PDB, etc.)
+	//   scaleTargetRef: {}
+	//     Injected to point at the versioned Deployment. Use this for HPAs, WPAs, and
+	//     other autoscaler CRDs that need a scale target.
+	//
+	//   spec.selector.matchLabels: {}
+	//     Injected with the versioned Deployment's pod selector labels. Use this for
+	//     PodDisruptionBudgets and other resources that select pods.
+	//
+	//   spec.metrics[*].external.metric.selector.matchLabels: {} (or with user labels)
+	//     The controller appends worker_deployment_name, worker_deployment_build_id, and
+	//     temporal_namespace to any External metric selector where matchLabels is present.
+	//     User labels (e.g. task_type: "Activity") coexist alongside the injected keys.
+	//     Do not set worker_deployment_name, worker_deployment_build_id, or
+	//     temporal_namespace manually — the webhook will reject them.
 	// +kubebuilder:validation:Required
 	// +kubebuilder:pruning:PreserveUnknownFields
 	Template runtime.RawExtension `json:"template"`