tofu(proxmox): download base image as import content-type for disk import_from

Co-Authored-By: Claude Opus 4.8 <[email protected]>

infra/tofu/variables.tf

@@ -167,12 +167,12 @@ variable "image_source" {
 
 variable "image_file_name" {
   description = <<-EOT
-    File name the cloud image is stored as on image_datastore. Proxmox `iso`-content
-    storage only accepts *.iso / *.img names, so a qcow2 URL must be saved with a
-    .img extension (Proxmox still reads it as qcow2 on import).
+    File name the cloud image is stored as on image_datastore. With `import`-content
+    storage (PVE 8.2+) the native .qcow2 name is used directly — the old .img rename
+    was an `iso`-content workaround and is no longer needed.
   EOT
   type        = string
-  default     = "debian-12-genericcloud-amd64.img"
+  default     = "debian-12-genericcloud-amd64.qcow2"
 }
 
 # --- cloud-init identity ----------------------------------------------------