Pre-Order Management for Bundles with Shared Inventory (Crossover SKUs)

Enable pre-order management for products with bundle structures. Currently, the app can't handle pre-orders where child components (SKUs) are shared across multiple bundles. This creates inventory control issues because pre-orders for one bundle reduce availability for others sharing the same child components.

This feature should allow the creation of hierarchical bundle pre-orders, track inventory for both parent and child SKUs during pre-orders, and deduct pre-orders from shared child SKU inventory.