chore: disable VM tailscale bootstrap for now

Remove tailscale auth/bootstrap from cloud-init and workflows, keeping VM provisioning focused on core network behind pfSense while preserving SSH key cloud-init setup.

terraform/variables.tf

@@ -71,9 +71,3 @@ variable "SSH_KEY_PUBLIC" {
   type        = string
   description = "Public SSH key injected via cloud-init"
 }
-
-variable "TS_AUTHKEY" {
-  type        = string
-  sensitive   = true
-  description = "Tailscale auth key used during cloud-init enrollment"
-}