docs(cdk): add JSDoc to dlqAlarm matching errorAlarm precedent

Follows the pattern established in task-orchestrator.ts for public alarm
properties.

Author: nizar-lahlali

cdk/src/constructs/approval-metrics-publisher-consumer.ts

@@ -85,6 +85,7 @@ export interface ApprovalMetricsPublisherConsumerProps {
 export class ApprovalMetricsPublisherConsumer extends Construct {
   public readonly fn: lambda.NodejsFunction;
   public readonly dlq: sqs.Queue;
+  /** CloudWatch alarm that fires when the DLQ has at least one poison-pill record. */
   public readonly dlqAlarm: cloudwatch.IAlarm;
 
   constructor(scope: Construct, id: string, props: ApprovalMetricsPublisherConsumerProps) {

cdk/src/constructs/fanout-consumer.ts

@@ -107,6 +107,7 @@ export interface FanOutConsumerProps {
 export class FanOutConsumer extends Construct {
   public readonly fn: lambda.NodejsFunction;
   public readonly dlq: sqs.Queue;
+  /** CloudWatch alarm that fires when the DLQ has at least one poison-pill record. */
   public readonly dlqAlarm: cloudwatch.IAlarm;
 
   constructor(scope: Construct, id: string, props: FanOutConsumerProps) {