feat(01-01): Next.js app + Docker Compose stack with network segmentation

- Next.js 15 app with Tailwind CSS v4, standalone output for Docker
- Root layout with de locale, page with Tessera placeholder
- Multi-stage Dockerfile for web with monorepo root context
- Docker Compose with 4 services: traefik, web, api, db
- Three segregated networks: frontend-net, backend-net, data-net (internal)
- Traefik v2.11 reverse proxy routing / to web, /api to api
- API strip prefix middleware for clean routing
- PostgreSQL 16-alpine with health checks and named volume
- Fixed API Dockerfile for pnpm monorepo node_modules structure
- Fixed Next.js standalone path for monorepo (apps/web/server.js)
- Fixed Traefik Docker API version compatibility
- Network segmentation: web NOT on data-net, api NOT on frontend-net

apps/web/postcss.config.mjs

@@ -0,0 +1,8 @@
+/** @type {import('postcss-load-config').Config} */
+const config = {
+  plugins: {
+    "@tailwindcss/postcss": {},
+  },
+};
+
+export default config;