aula-12: Victoria Metrics + Grafana via GitOps

Stack completo de observabilidade:
- Victoria Metrics (vmsingle, vmagent, vmalert)
- Grafana com dashboards built-in
- Alertas customizados (PVC, pods, nodes, deployments)
- pvc-autoresizer para expansão automática de volumes
- Queries PromQL documentadas

Instalação via ArgoCD seguindo padrão GitOps da aula-11.

aula-12/gitops/apps/victoria-metrics/Chart.yaml

@@ -0,0 +1,11 @@
+apiVersion: v2
+name: monitoring-stack
+description: Victoria Metrics stack for Kubernetes monitoring
+type: application
+version: 1.0.0
+appVersion: "1.0.0"
+
+dependencies:
+  - name: victoria-metrics-k8s-stack
+    version: "0.28.4"
+    repository: https://victoriametrics.github.io/helm-charts/