feat: добавить prometheus-метрики ко всем оставшимся аддонам

- cert-manager: prometheus.enabled + servicemonitor (port 9402)
- ingress-nginx: динамический ServiceMonitor вместо захардкоженного false
- ArgoCD: metrics.enabled для всех компонентов (server, repoServer, applicationSet, notifications, controller)
- Longhorn: metrics.serviceMonitor.enabled
- Istio: ServiceMonitor для istiod (port http-monitoring), enablePrometheusMerge для sidecar-метрик, fix istio_telemetry_enabled → istio_metrics_enabled в шаблоне

Во всех случаях ServiceMonitor создаётся только при addon_prometheus_stack: true.

addons/argocd/role/defaults/main.yml

@@ -12,6 +12,10 @@ argocd_ingress_class: "{{ ingress_nginx_class_name | default('nginx') }}"
 argocd_ingress_tls: false
 argocd_ingress_cert_issuer: "{{ cert_manager_default_issuer_name | default('letsencrypt-prod') }}"
 
+# ── Метрики (встроены в каждый компонент) ────────────────────────────────────
+argocd_metrics_enabled: true
+# ServiceMonitor создаётся только когда addon_prometheus_stack: true
+
 argocd_resources:
   requests:
     cpu: 50m

addons/argocd/role/tasks/main.yml

@@ -22,12 +22,33 @@
       server:
         insecure: "{{ argocd_insecure | bool }}"
         resources: "{{ argocd_resources }}"
+        metrics:
+          enabled: "{{ argocd_metrics_enabled | bool }}"
+          serviceMonitor:
+            enabled: "{{ argocd_metrics_enabled | bool and addon_prometheus_stack | default(false) | bool }}"
       repoServer:
         resources: "{{ argocd_resources }}"
+        metrics:
+          enabled: "{{ argocd_metrics_enabled | bool }}"
+          serviceMonitor:
+            enabled: "{{ argocd_metrics_enabled | bool and addon_prometheus_stack | default(false) | bool }}"
       applicationSet:
         resources: "{{ argocd_resources }}"
+        metrics:
+          enabled: "{{ argocd_metrics_enabled | bool }}"
+          serviceMonitor:
+            enabled: "{{ argocd_metrics_enabled | bool and addon_prometheus_stack | default(false) | bool }}"
       notifications:
         resources: "{{ argocd_resources }}"
+        metrics:
+          enabled: "{{ argocd_metrics_enabled | bool }}"
+          serviceMonitor:
+            enabled: "{{ argocd_metrics_enabled | bool and addon_prometheus_stack | default(false) | bool }}"
+      controller:
+        metrics:
+          enabled: "{{ argocd_metrics_enabled | bool }}"
+          serviceMonitor:
+            enabled: "{{ argocd_metrics_enabled | bool and addon_prometheus_stack | default(false) | bool }}"
       redis:
         resources:
           requests: