Reversed the product sync direction: instead of pulling all 60k+ items
from BC and matching against WooCommerce (600+ paginated API calls that
timeout), now iterates the ~100 WooCommerce products and queries BC for
each one by GTIN/item number (1-2 API calls per product).
Added Location Code setting (e.g. "ICP") to filter stock by BC location.
Uses Item Ledger Entries endpoint to sum per-location stock. Falls back
to total inventory if the endpoint is unavailable.
Also registered wbc_location_code in sync settings group and uninstall.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>