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/group_vars/servers.yaml

@@ -0,0 +1,12 @@
+---
+k3s_server_args: >-
+  --cluster-cidr={{ cluster_cidr }}
+  --service-cidr={{ service_cidr }}
+  --cluster-dns={{ cluster_dns }}
+  --disable=servicelb
+  --write-kubeconfig-mode=644
+  --tls-san={{ ansible_host }}
+  --tls-san=k3s.homelab.local
+  --kube-apiserver-arg=audit-log-maxage=30
+  --kube-apiserver-arg=audit-log-maxbackup=10
+  --kube-apiserver-arg=audit-log-maxsize=100