Initial monorepo scaffold

Turborepo + pnpm monorepo for k3s homelab cluster on Intel NUCs.

- Apps: Next.js web frontend, Express API (TypeScript, Dockerfiles, k8s manifests)
- Packages: shared UI, ESLint config, TypeScript config, Drizzle DB schemas
- Infra/Ansible: bare-metal provisioning with roles for common, k3s-server, k3s-agent, hardening
- Infra/Kubernetes: ArgoCD GitOps (app-of-apps + ApplicationSets), platform components
  (cert-manager, Traefik, CloudNativePG, Valkey, Longhorn, Sealed Secrets), namespaces
- Observability: kube-prometheus-stack, Loki, Promtail as ArgoCD Applications
- CI/CD: GitHub Actions for PR builds, preview deploys, production deploys
- DX: Taskfile, utility scripts, copier templates, Ubiquiti network docs

infra/ansible/roles/k3s-agent/tasks/main.yaml

@@ -0,0 +1,29 @@
+---
+- name: Check if k3s-agent is installed
+  ansible.builtin.stat:
+    path: /usr/local/bin/k3s
+  register: k3s_binary
+
+- name: Download k3s installer
+  ansible.builtin.get_url:
+    url: https://get.k3s.io
+    dest: /tmp/k3s-install.sh
+    mode: "0755"
+  when: not k3s_binary.stat.exists
+
+- name: Install k3s agent
+  ansible.builtin.command:
+    cmd: /tmp/k3s-install.sh
+  environment:
+    INSTALL_K3S_VERSION: "{{ k3s_version }}"
+    K3S_URL: "{{ k3s_server_url }}"
+    K3S_TOKEN: "{{ k3s_token }}"
+    INSTALL_K3S_EXEC: "agent {{ k3s_agent_args }}"
+  when: not k3s_binary.stat.exists
+  changed_when: true
+
+- name: Wait for k3s-agent to be ready
+  ansible.builtin.systemd:
+    name: k3s-agent
+    state: started
+    enabled: true