CI/CD Pipeline: Add GitHub Actions workflow

[OneByJorah]

CI/CD Pipeline Gap

Current State: No CI/CD pipeline configured. No automated testing, building, or deployment.

Required:

1. Create GitHub Actions workflow () with:

   • Linting (flake8/ruff for Python, ESLint for JS)
   • Type checking (mypy for Python, TypeScript if migrated)
   • Unit tests (pytest for backend, Jest for frontend)
   • Integration tests
   • Docker image building and pushing to GHCR
   • Security scanning (as per Security Audit issue)
   • Deployment to staging/production environments

2. Add test dependencies to requirements.txt and package.json

3. Add test scripts to package.json and Makefile/pyproject.toml

4. Configure branch protection rules on main branch

5. Add semantic versioning and changelog generation

Priority: HIGH