Set up self-contained Docker Compose development environment

[jenul-ferdinand]

Goal

• Let contributors start the Angular frontend, Express backend, and MongoDB with one Docker Compose command.
• Give each contributor a self-contained development database with realistic synthetic data, without MongoDB Atlas credentials.
• Preserve hot reload for frontend and backend source changes during local development.

Implementation

• Add development Dockerfiles and .dockerignore files for the frontend and backend.
• Add a compose.yaml with frontend, backend, and MongoDB services plus a named database volume.
• Configure the service network and set the backend MongoDB connection string to the Compose service name.
• Pass backend secrets through an untracked environment file and provide a safe example file.
• Add health checks and dependency conditions so Compose reports service readiness.
• Add a documented seed process that creates a realistic, fictional dataset for local development. It must include users and the related data needed to exercise core contributor workflows.
• Make the seed process safe to repeat and document how contributors can reset their local database and restore the sample data.
• Update the contributing guide with prerequisites and commands for startup, logs, shutdown, database reset, and seed data.
• Keep the existing npm-based development workflow available outside Docker.

Acceptance criteria

• docker compose up --build starts all three services from a fresh checkout after the contributor creates the documented environment file.
• The frontend responds at http://localhost:4200 and the backend responds at http://localhost:8080.
• Frontend API requests reach the backend, and the backend connects to the containerized MongoDB instance without host-installed services or MongoDB Atlas.
• A first-run local database contains synthetic sample data that lets a contributor use and develop the core application flows.
• The sample data contains no production data, real credentials, or information about real users.
• Contributors can reset their database and restore the sample data with documented commands.
• Frontend and backend source changes trigger their development reloaders without an image rebuild.
• MongoDB data survives docker compose down, and the documentation includes the command that removes the volume for a clean reset.
• Docker build contexts exclude dependencies, build output, Git metadata, and environment files.
• The repository contains no committed credentials or local environment values.