In this disposable workspace, create a Python standard-library CLI that reads a local CSV with columns item and quantity, rejects invalid or negative quantities, and prints the total quantity. No network calls or extra dependencies. Before implementation, load brief2ship and run bounded local-only CLI discovery; do not query public sources for this offline task. Keep the receipt and resolve any inconclusive decision explicitly. If the CLI is unavailable, label manual local discovery degraded preflight. Write tests for valid input, empty input, missing columns and invalid quantities. Run the tests, run the actual CLI against a fixture, and leave a README with exact commands plus a HANDOFF describing real results. Do not publish anything.
