Record a real walkthrough

After building, run npm run record:demo. This opt-in workflow records desktop and mobile viewports in isolated browser contexts with no provider keys. The Arabic walkthrough records browsing, color/storage choice, delivery, extras, customer details, review, order confirmation, and demo payment. The recordings, final screenshots, and measured chapter timestamps are saved under test-results/demo/. These are recordings of the working application with fictional demo products, not generated video or real purchases. Reading pauses are intentional; normal browser verification does not include this recorder.