- add discontinued status to products (soft-delete when removed from provider)
- add availability helpers to variants (available/out_of_stock/discontinued)
- add detailed sync audit logging (product created/updated/discontinued)
- add cost change detection with threshold alerts (5% warning, 20% critical)
- update cart to show unavailable items with appropriate messaging
- block checkout when cart contains unavailable items
- show discontinued badge on product pages
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
