ci: storage VM uses public DNS — the CI VLAN gateway runs no resolver

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/infrastructure/storage-vm.tf

@@ -49,7 +49,7 @@ resource "proxmox_virtual_environment_vm" "storage" {
     }
 
     dns {
-      servers = [var.storage_vm_gateway]
+      servers = [var.storage_vm_dns]
     }
 
     user_account {

tests/infrastructure/variables.tf

@@ -102,11 +102,17 @@ variable "storage_vm_ssh_public_key" {
 }
 
 variable "storage_vm_gateway" {
-  description = "Gateway (and DNS server) for the storage VM"
+  description = "Gateway for the storage VM"
   type        = string
   default     = "172.16.60.1"
 }
 
+variable "storage_vm_dns" {
+  description = "DNS server for the storage VM. The CI VLAN gateway runs no resolver; public DNS works under the ci-to-internet rule and keeps the sandbox independent of fleet DNS"
+  type        = string
+  default     = "1.1.1.1"
+}
+
 variable "cloud_image_path" {
   description = "Local path to the Ubuntu cloud image imported as the storage VM's disk (required for provision; unused on destroy)"
   type        = string