Add production Docker image

[amicus-merakisys]

Summary

• replace the default Dockerfile with a multi-stage production image that builds the React app and serves the static output with nginx
• add nginx config for SPA fallback routing, long-lived hashed asset caching, and no-cache service worker delivery
• update docker compose and README commands for the production container port
• add .dockerignore to keep the Docker context clean

Why this matters

The previous Dockerfile was optimized for local development: it installed dependencies, copied the source tree, and ran the React development server. That works for contributor workflows, but it is heavier and less predictable for deployment. A production image should compile once, ship only the generated static assets, and serve them from a small web server.

Making the main Dockerfile production-ready means the default Docker path now matches how this viewer should be deployed: smaller runtime surface, faster startup, static asset caching, and proper SPA fallback behavior.

Testing

• NODE_OPTIONS=--openssl-legacy-provider npm run build
• Could not run docker build in this environment because Docker daemon access is unavailable: permission denied connecting to /var/run/docker.sock

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}