feat: add bare bones Proxmox Terraform scaffold

Adds provider config, variables, and an example tfvars file using
the bpg/proxmox provider. No resources are managed yet — existing
Proxmox setup is untouched.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

main.tf

@@ -0,0 +1,19 @@
+terraform {
+  required_version = ">= 1.0"
+
+  required_providers {
+    proxmox = {
+      source  = "bpg/proxmox"
+      version = "~> 0.73"
+    }
+  }
+}
+
+provider "proxmox" {
+  endpoint = var.proxmox_endpoint
+  username = var.proxmox_username
+  password = var.proxmox_password
+
+  # Set to true if using a self-signed certificate (common on home labs)
+  insecure = var.proxmox_insecure
+}