Complete design spec for bidirectional Odoo 19 <-> WooCommerce sync system covering product mapping, order lifecycle, inventory sync, customer portal, and all supporting data models. Addresses all review findings including variant support, tax/pricelist mapping models, return/RMA workflow, multi-shipment tracking, and Odoo 19 technical requirements. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>