One catalogue should be enough
Independent dealers already photograph their pieces, write descriptions, set prices and update availability. Asking them to repeat that work inside PatinaHall would make the marketplace part of the problem.
Shopify should remain the shop's working catalogue. PatinaHall's role is to bring it into a focused furniture and antiques marketplace without turning every change into another task.
What sellers can do today
PatinaHall can accept a public Shopify store address, prepare a private catalogue view and let the seller import all eligible products or a selected group as private drafts. The seller sees what was found before deciding what to bring in.
Importing a draft does not publish it. The seller can review the result, and PatinaHall does not show a product to buyers merely because it appeared in Shopify.
What still comes next
A seller can request a fresh catalogue check, but ongoing updates are not automatic yet. A price or availability change in Shopify does not yet update a PatinaHall listing automatically.
Dependable ongoing synchronisation is the next part of the promise. We will call it automatic only when sellers can see how it works, remain in control and trust it not to create another system to babysit.