Dockerise the app for one-command deployment via docker-compose

[ibsule]

Problem

The application currently lacks Dockerisation, making it more challenging to deploy in unified environments such as VPS servers.

Request

• Add support to Dockerise the app so that running docker compose up in a VPS will get it up and running.
• Ensure all dependencies, services, and environment variables are handled in the Docker setup.
• Provide working Dockerfile and docker-compose.yml files at the project root.
• Add clear instructions in the README (or a new DEPLOY.md) for usage.

Acceptance Criteria

• Cloning the repo and running docker compose up should start all necessary services (front-end, back-end, DB or cache if needed).
• No manual steps required beyond configuring environment variables as documented.
• The solution should be suitable for deployment on commonly-available VPS hosts.

Notes

• The project is mainly TypeScript (Node.js), with minor Handlebars, JS, CSS content.
• If there are app-specific build steps, ensure they are represented in the Docker setup.