feat: Add HA Kubernetes cluster with Terraform + Ansible

- 3x CX23 control plane nodes (HA)
- 4x CX33 worker nodes
- k3s with embedded etcd
- Hetzner CCM for load balancers
- Gitea CI/CD workflows
- Backblaze B2 for Terraform state

terraform/ssh.tf

@@ -0,0 +1,8 @@
+data "local_file" "ssh_public_key" {
+  filename = pathexpand(var.ssh_public_key)
+}
+
+resource "hcloud_ssh_key" "cluster" {
+  name       = "${var.cluster_name}-ssh-key"
+  public_key = data.local_file.ssh_public_key.content
+}