Production runs demo mode with no PayPal credentials — that combination is the whole reason #191 turned it on — and in exactly that configuration the storefront rendered a full-width primary button reading plainly `Checkout`. The `(Demo)` suffix was gated on a PayPal client id being present, so the one configuration that needs the word was the only one that never got it. The button is not decorative. It posts to `/demo/purchase`, which marks the item `sold`, writes a `completed` row into `orders` at the real price, and emails everyone who favorited it through production's real SMTP. Nobody is charged, which is what the compose banner promises and is true — but a customer cannot tell they have placed a pretend order, the inventory says otherwise, other customers are told it sold, and nobody is expecting to ship anything. #190, #191 and #192 all reason carefully about not charging by accident; none of them consider accepting an order by accident. Three things now say so, because one of them was never going to be enough: The label is unconditional. `type` still follows the PayPal client id — secondary when real PayPal buttons sit above it, primary when it is the only way to check out — and that distinction is worth keeping, but it is about prominence rather than about what the order is. A notice sits above it for the whole of demo mode, before an address is picked and whether or not PayPal is configured. A parenthesis on the control someone has already decided to press is the weakest possible moment to tell them. The confirmation stopped saying `Order complete!`, which is exactly what a real order says. It now names the two things a customer would otherwise assume: nothing was charged, and nothing will be shipped. Three end-to-end tests, written first and failing first against a browser — the label assertion failed with `Expected "Checkout (Demo)", Received "Checkout"` on an `ant-btn-primary ant-btn-block` element, which is the defect exactly as reported. The suite already runs `DEMO_MODE=true` with no PayPal credentials, so it reproduces production's configuration without any new fixture. `CartPage.checkoutButton` matches the label by prefix rather than in full, deliberately: a locator naming the correct label would have gone looking for the right button and found nothing, which is how a test for this can quietly pass by being wrong in the same direction as the bug. Verified: 3 new tests pass, frontend build clean, lint 0 errors, 25 unit tests pass, and the cart-countdown and orders suites still pass. The favorites and favorites-filter suites fail here, and fail identically with this change stashed — 9 failures without it, 8 with — so they are pre-existing and not from this. Worth their own issue. Closes #195 Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>