feat(aula-08): adicionar seleção de arquitetura (arm64/amd64) e detectar tofu/terraform

- Variável `arch` no Terraform: arm64 (CAX11 em nbg1) ou amd64 (CPX21 em fsn1)
- locals map traduz arch → server_type + location
- setup.sh pergunta arquitetura interativamente (default: arm64)
- Detecta OpenTofu ou Terraform automaticamente (preferência tofu)
- Autoscaler: sed troca CAX→CPX nos server_types quando amd64
- tfvars gerado inclui arch selecionado

aula-08/main.tf

@@ -38,6 +38,19 @@ locals {
   # Endpoint: LoadBalancer IP if enabled, otherwise Floating IP
   cluster_endpoint_ip = var.enable_loadbalancer ? hcloud_load_balancer.cluster[0].ipv4 : hcloud_floating_ip.control_plane[0].ip_address
 
+  # Arquitetura: mapeia arm64→CAX (Nuremberg) ou amd64→CPX (Frankfurt)
+  arch_config = {
+    arm64 = {
+      server_type_cp = "cax11"
+      location       = "nbg1"
+    }
+    amd64 = {
+      server_type_cp = "cpx21"
+      location       = "fsn1"
+    }
+  }
+  selected_arch = local.arch_config[var.arch]
+
   common_labels = {
     cluster     = local.cluster_name
     environment = var.environment
@@ -192,15 +205,15 @@ resource "hcloud_placement_group" "cluster" {
 }
 
 ############################################################
-# CONTROL PLANE NODES (HA with 3 CAX11 nodes)
+# CONTROL PLANE NODES (HA com 3 nodes)
 ############################################################
 
 resource "hcloud_server" "control_plane" {
   count       = local.control_plane_count
   name        = "${local.cluster_name}-cp-${count.index}"
-  server_type = "cax11"
+  server_type = local.selected_arch.server_type_cp
   image       = data.hcloud_image.talos.id
-  location    = "nbg1"  # CAX11 only available in Nuremberg
+  location    = local.selected_arch.location
   ssh_keys    = [local.ssh_key_id]
 
   firewall_ids       = [hcloud_firewall.cluster.id]
@@ -209,7 +222,7 @@ resource "hcloud_server" "control_plane" {
   labels = merge(local.common_labels, {
     role = "control-plane"
     node = "cp-${count.index}"
-    arch = "arm64"
+    arch = var.arch
   })
 
   public_net {
@@ -373,15 +386,15 @@ resource "hcloud_load_balancer_target" "worker" {
 }
 
 ############################################################
-# WORKER NODE (Single CAX11)
+# WORKER NODE
 ############################################################
 
 resource "hcloud_server" "worker" {
   count       = 1
   name        = "${local.cluster_name}-worker-${count.index}"
-  server_type = "cax11"
+  server_type = local.selected_arch.server_type_cp
   image       = data.hcloud_image.talos.id
-  location    = "nbg1"
+  location    = local.selected_arch.location
   ssh_keys    = [local.ssh_key_id]
 
   firewall_ids       = [hcloud_firewall.cluster.id]
@@ -390,7 +403,7 @@ resource "hcloud_server" "worker" {
   labels = merge(local.common_labels, {
     role = "worker"
     node = "worker-${count.index}"
-    arch = "arm64"
+    arch = var.arch
   })
 
   public_net {