feat: Add Docker support with multi-stage build

[slmingol]

Overview

This PR adds comprehensive Docker support for the React Connections Game project.

Changes

• Dockerfile: Multi-stage build using Node.js 18 (Debian-based) for building and Nginx Alpine for serving
• docker-compose.yml: Full setup with local build capability and optional dev mode with hot-reload
• docker-compose.simple.yml: Simplified setup for running from GitHub Container Registry
• .dockerignore: Optimizes build context by excluding unnecessary files

Usage

Production Build (Local)

docker-compose up -d

Access at http://localhost:3000

From GHCR (once published)

docker-compose -f docker-compose.simple.yml up -d

Technical Notes

• Uses Debian-based Node image (not Alpine) for ARM compatibility with Parcel's native modules
• Multi-stage build keeps production image small - Multi-stage build keeps production image small - Multi-stage build keeps production image small - Multi-stage build keeps production image small - Multi-stage build keepom fork: https://github.com/slmingol/react-connections-game