feat(01-01): Next.js 15 project with Docker Compose dev environment

- Next.js 15 with App Router, TypeScript, Tailwind CSS (v4), ESLint
- docker-compose.yml with PostgreSQL 16, Redis 7, and app service
- Dockerfile (Node 20 alpine) for containerized development
- .env and .env.example with DATABASE_URL, DATABASE_URL_LOCAL, REDIS_URL
- src/app/page.tsx updated to render NetForge heading
- All three services start healthy with docker compose up -d

postcss.config.mjs

@@ -0,0 +1,7 @@
+const config = {
+  plugins: {
+    "@tailwindcss/postcss": {},
+  },
+};
+
+export default config;