Add Docker and CI Support

[CloCkWeRX]

This PR introduces full containerization support for the Rails application.

Changes:

• Dockerfile: Uses a ruby:3.3.8-bullseye base image. It includes all necessary system dependencies, handles gem and JS package installation, and performs asset precompilation for production.
• Docker Compose: Sets up the application with its primary dependencies:
  • web: The Rails application.
  • db: PostgreSQL 17, using existing initialization scripts.
  • elasticsearch: Elasticsearch 7.4.0, matching the version required by the application.
• CI/CD: A new GitHub Actions workflow automates the building and publication of the Docker image to the GitHub Container Registry (GHCR) whenever changes are pushed to the dev branch.
• Entrypoint: A script ensures that stale Rails server PIDs are cleared before the container starts.

These changes provide a consistent development and production-like environment and automate the container image lifecycle.

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PR created automatically by Jules for task 2313436152704642708 started by @CloCkWeRX

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