routes/paypal.ts and routes/demo.ts were the pre-cart single-item
checkout flow. Nothing has imported them since the cart flow landed:
app.ts mounts only cartCheckout, the frontend calls /api/checkout/cart/*,
and no test touches them. They duplicated PAYPAL_BASE, getAccessToken,
and a second handler for the /webhooks/paypal mount.
Also extract openCheckout() from /paypal/create and /demo/purchase in
cartCheckout.ts, which repeated the same address-ownership check, cart
lock, and checkouts/checkout_items inserts. It returns a discriminated
union so callers keep control of the transaction and the response. Add
CartItem/LockedCart interfaces, dropping the (it: any) casts.
Note: paypal.ts was the only writer of items.reserved_until and
items.paypal_order_id. Those columns are now write-dead; the schema is
left alone for a separate migration.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>