HYPERFLEET-856 - fix: correct alert description to include stuck threshold

The metric already embeds a 30m stuck threshold from the collector,
so the actual time before the alert fires is threshold + alert delay.
Update descriptions to clarify both components.

Author: rafabene

charts/templates/prometheusrule.yaml

@@ -22,7 +22,8 @@ spec:
             summary: "HyperFleet resources stuck in Pending Deletion state"
             description: >-
               {{ "{{ $value }}" }} {{ "{{ $labels.resource_type }}" }} resource(s) have been in
-              Pending Deletion state for more than {{ .Values.prometheusRule.rules.deletionStuck.for | default "5m" }}.
+              Pending Deletion state for more than {{ .Values.config.metrics.deletion_stuck_threshold | default "30m" }}
+              (stuck threshold) + {{ .Values.prometheusRule.rules.deletionStuck.for | default "5m" }} (alert delay).
             runbook_url: {{ .Values.prometheusRule.rules.deletionStuck.runbookUrl | default "" | quote }}
         - alert: HyperFleetResourceDeletionStuckCritical
           expr: max by (namespace, resource_type)(hyperfleet_api_resource_pending_deletion_stuck) > 0
@@ -33,6 +34,7 @@ spec:
             summary: "HyperFleet resources timed out in Pending Deletion state"
             description: >-
               {{ "{{ $value }}" }} {{ "{{ $labels.resource_type }}" }} resource(s) have been in
-              Pending Deletion state for more than {{ .Values.prometheusRule.rules.deletionTimeout.for | default "30m" }}. Immediate investigation required.
+              Pending Deletion state for more than {{ .Values.config.metrics.deletion_stuck_threshold | default "30m" }}
+              (stuck threshold) + {{ .Values.prometheusRule.rules.deletionTimeout.for | default "30m" }} (alert delay). Immediate investigation required.
             runbook_url: {{ .Values.prometheusRule.rules.deletionTimeout.runbookUrl | default "" | quote }}
 {{- end }}