Environment Setup

When setting up environment configuration:

1. Create a .env.example file listing every required variable with placeholder values and comments.
2. Create a config module that reads all env vars in one place and exports typed objects.
3. Validate required variables at startup — fail fast with a clear error if any are missing.
4. Never access process.env directly outside the config module.
5. Add .env to .gitignore. Verify it’s not tracked before committing.
6. Document which variables are required vs optional and what values they expect.