feat: migrate vm-system to ArgoCD (#80)

Migrate Victoria Metrics operator from Terragrunt to ArgoCD/Kustomize.
Deploys victoria-metrics-operator v0.57.1 with 2 replicas in vm-system.

💘 Generated with Crush

Assisted-by: Claude Sonnet 4.6 via Crush <crush@charm.land>

Reviewed-on: #80

argocd/applicationsets/platform.yaml

@@ -24,6 +24,7 @@ spec:
       - path: apps/overlays/*/reflector-system
       - path: apps/overlays/*/reloader-system
       - path: apps/overlays/*/reposync
+      - path: apps/overlays/*/vm-system
       - path: apps/overlays/*/woodpecker
   template:
     metadata:

argocd/projects/platform.yaml

@@ -14,6 +14,7 @@ spec:
     - https://intel.github.io/helm-charts/
     - https://kubernetes-sigs.github.io/external-dns/
     - https://releases.rancher.com/server-charts/stable
+    - https://victoriametrics.github.io/helm-charts/
     - oci://gcr.io/k8s-staging-nfd/charts
     - oci://ghcr.io/emberstack/helm-charts
     - oci://ghcr.io/woodpecker-ci/helm/woodpecker