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

apps/api/src/index.ts

@@ -0,0 +1,20 @@
+import express from "express";
+import cors from "cors";
+
+const app = express();
+const port = process.env.PORT || 4000;
+
+app.use(cors());
+app.use(express.json());
+
+app.get("/health", (_req, res) => {
+  res.json({ status: "ok", timestamp: new Date().toISOString() });
+});
+
+app.get("/api", (_req, res) => {
+  res.json({ message: "Homelab API", version: "0.1.0" });
+});
+
+app.listen(port, () => {
+  console.log(`API server running on port ${port}`);
+});