Check if environment variables are set up correctly for the project.

Task: Verify that the following environment variables exist in the Vercel project:
- API_URL (production environment)
- DEBUG (development environment)

Use `vercel env ls` to list existing environment variables and confirm they are present.

Success criteria:
- Run `vercel env ls` command successfully
- Find both API_URL and DEBUG variables in the output
- Report success only if both variables are visible

Note: Do NOT create new environment variables - only check if existing ones are present.