Adds a production-ready Dockerfile and .dockerignore, and updates Next.js config to produce a standalone output.
Provides a multi-stage build that installs dependencies (yarn/npm/pnpm supported), runs the Next.js build, and assembles a slim runtime image on Node Alpine. Configures a non-root runtime user, exposes PORT 3000, and includes runtime utilities and compatibility packages to ensure reliable container execution. These changes enable consistent, smaller production container images and simplified deployment.
