Use this before listing.create / listing.publish to confirm the target sales channel is connected, or before social_post.publish to confirm the social account is linked.
Returns
Connected marketplaces. Each: provider ("etsy" / "shopify" / "tiktok_shop"), status, store_name, store_id, connected_at.
Connected POD providers. Each: provider ("printful" / "printify"), status, store_name, store_id, linked_channel ({provider, store_name, store_id} of the marketplace it fulfills, or null), connected_at. One Printify connection expands to one entry per shop.
Connected social profiles. Each: provider (e.g. "instagram" / "tiktok" / "youtube" / "x"), status, username (or null), connected_at.