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/inventory/hosts.yaml

@@ -0,0 +1,18 @@
+---
+all:
+  children:
+    k3s_cluster:
+      children:
+        servers:
+          hosts:
+            nuc01:
+              ansible_host: 10.0.10.11
+              k3s_role: server
+        agents:
+          hosts:
+            nuc02:
+              ansible_host: 10.0.10.12
+              k3s_role: agent
+            nuc03:
+              ansible_host: 10.0.10.13
+              k3s_role: agent