docs: Add professional README.md with comprehensive setup instructions

[orbaps]

Change(s)

Change Type: Added

Change Category: Documentation

Changelog Entry: Added a comprehensive README.md to the root of the repository.

The new README includes a professional layout with badges, architecture overview, prerequisites, and clear setup instructions for both Docker Compose and local development. It also covers API usage (Swagger UI), monitoring, and contribution guidelines to help new users and contributors get started easily.

How to Test

This is a documentation-only change. Reviewers can preview the markdown rendering of the README.md file in the GitHub PR "Files changed" tab to ensure formatting, links, and badges display correctly.

Checklist

• Tests have been added or updated to reflect the changes, or their absence is explicitly explained.
• Documentation has been added or updated to reflect the changes, or their absence is explicitly explained.
• A self-review has been conducted checking:
  • No unintended changes have been committed.
  • The changes in isolation seem reasonable.
  • Anything that may be odd or unintuitive is provided with a GitHub comment explaining it (but consider if this should not be a code comment or in the documentation instead).
• All CI checks pass before pinging a reviewer, or provide an explanation if they do not.
• The PR title matches the changelog entry's one-line description.

Related Issues

Closes #733