Bundles group product variants sold together as a single sellable unit: a meal combo, a starter kit, a multi-pack. A bundle has its own price, SKU, image, tax settings, and categories, independent of its components. Each component references a product variant with a quantity and display position.
Bundles are sellable the same way variants are: pass a bundle_id on an order line item and Flint resolves price and display from the catalog. Bundle availability is computed from component inventory, so a bundle is only available_for_sale while every component variant has sufficient stock. Bundles can also carry modifier set assignments for buyer customization.
