Parses additional packaging formats from option1 and falls back to SKU
parsing for single-variant products with 'Default Title'.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Fetches all products and variants from Shopify API, creates local
Products, Packings and ProductSizes with shopify_variant_id, and
fills ProductInventory rows to match Shopify's inventory_quantity.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>