Build Core E-Commerce Backend (Replacing Shopify) API, Orders, Inventory, Lynk WMS Integration

We're moving away from Shopify and need a clean, reliable, minimal backend that fully replaces Shopify's core functions:

- Orders
- Checkout integration (payments handled separately)
- Product/SKU catalogue
- Inventory sync
- Fulfilment push to Lynk (our warehouse)
- Tracking + status updates back to our DB

This is NOT a full website build.

Experience Level: Intermediate
Duration: 3-6 months
Hours: More than 30 hrs/week