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/Dockerfile

@@ -0,0 +1,25 @@
+FROM node:20-alpine AS base
+
+FROM base AS deps
+WORKDIR /app
+COPY package.json pnpm-lock.yaml* ./
+RUN corepack enable pnpm && pnpm install --frozen-lockfile
+
+FROM base AS builder
+WORKDIR /app
+COPY --from=deps /app/node_modules ./node_modules
+COPY . .
+RUN corepack enable pnpm && pnpm build
+
+FROM base AS runner
+WORKDIR /app
+ENV NODE_ENV=production
+RUN addgroup --system --gid 1001 nodejs
+RUN adduser --system --uid 1001 appuser
+COPY --from=builder /app/dist ./dist
+COPY --from=builder /app/node_modules ./node_modules
+COPY --from=builder /app/package.json ./
+USER appuser
+EXPOSE 4000
+ENV PORT=4000
+CMD ["node", "dist/index.js"]