Cross-device sync only ever worked one way (local→server on every
change via CartSync) plus a server→local merge at the exact moment of
login/register — a customer already signed in on a second device (no
fresh login action happening) never picked up changes made elsewhere.
Adds pullServerCart(): idempotent (server qty overwrites a matching
local line rather than adding to it, safe to call repeatedly, unlike
mergeServerCartIntoLocal()'s additive merge which only stays correct
right after a login clears the local cart's ambiguity). Triggered on
CartSync's mount and on window focus — covers "open the site while
already logged in" and "switch back to this tab after changing the
cart on another device," without a polling interval.
Checkout now persists orders server-side (Payload orders collection,
re-priced from live product data, discount codes redeemed exactly once)
instead of writing a client-only sessionStorage snapshot. Buying requires
an account (registration inline in checkout, no separate step) — accounts
get order history with delivery status, profile/address editing, password
change, and a cart that syncs across devices while logged in.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Marco