Add Railway ignore file and update Docker and package configurations

Commit notes

- Created .railwayignore to exclude frontend files and root-level configs from Railway deployments, ensuring only backend files are processed. - Updated docker-compose.yml to change PostgreSQL port mapping from 5432 to 5433. - Removed outdated Dockerfile and Makefile to streamline the project structure. - Renamed package.json to reflect the new monorepo structure and updated dependencies accordingly. - Introduced pnpm-workspace.yaml to define workspace packages for better dependency management. - Added README.md to provide an overview of the project structure and features.