Keep linked Shopify listings in stock together

Shared Stock Linker syncs sellable inventory across duplicate or alternate listings that should draw from the same stock pool.

• Link variants into one shared-stock group. Keep related listings aligned without manual inventory edits.
• React to orders, refunds, and manual changes. The app keeps the linked variants' available quantity in sync.
• Detect drift instead of guessing. When inventory looks ambiguous, the app flags the group for review and reconcile.