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/network.tf

@@ -0,0 +1,11 @@
+resource "hcloud_network" "cluster" {
+  name     = "${var.cluster_name}-network"
+  ip_range = var.network_cidr
+}
+
+resource "hcloud_network_subnet" "servers" {
+  network_id   = hcloud_network.cluster.id
+  type         = "cloud"
+  network_zone = "${var.location}-network"
+  ip_range     = var.subnet_cidr
+}