Shopify — fix store not linking when launched from Shopify admin

Opening the PixTwins app from inside your Shopify store admin now correctly connects the store to your workspace. Previously the OAuth round-trip would finish but silently fail to save the connection, leaving you on the chat page with no store linked.

• ›Logging in from the Shopify admin app launcher now links the store to your active workspace
• ›Connection from the Integrations page (enter-a-shop-domain flow) is unchanged