feat(opentofu): define bare-metal host configuration

opentofu/modules/proxmox-node/variables.tf

@@ -0,0 +1,15 @@
+variable "node_name" {
+  type        = string
+  description = "The name of the Proxmox node (e.g. pve)"
+}
+
+variable "data_disk_id" {
+  type        = string
+  description = "The persistent block device ID for the data disk (e.g. wwn-0x500...)"
+}
+
+variable "zfs_pool_name" {
+  type        = string
+  default     = "data"
+  description = "The name of the ZFS pool to create on the data disk"
+}