Resolve product description + derive selling points

Resolve the two product-sourced personalization blocks for one of your products: [Product Description] (the product's own catalog text) and [Product Selling Points] (2–3 concrete selling points DERIVED from the product's real title/description/attributes — never invented). Use the returned strings verbatim in POST /personalization/preview and in the personalization block of POST /automations/dm, so preview and send share the same fixed copy.

Both blocks degrade to empty strings (the block simply drops out of the message) ONLY when the product isn't in this shop's catalog or has too little grounded content; a failed lookup (transient database error) returns 500 instead, so empty strings are always a true statement about the product, never an outage artifact — safe to store. Requires a single shop.