Product carousel now matches what the assistant actually recommends

The product carousel could get out of sync with the assistant's answer. Three cases:

• The assistant would say it found no good match, while the carousel still showed products from an earlier search.
• If the assistant searched more than once in the same turn (for example, retrying with a broader query), each search added its own carousel, including one from a search it had already abandoned.
• If the assistant ran two searches in one turn (for example, a skincare routine for face and body), the carousel could end up hidden behind a collapsed "N tool calls" panel, so the shopper saw no products at all unless they clicked to expand it.

The carousel now renders only the products the assistant has actually decided to show, after it has picked its final selection, never straight from a search result. It also always displays in full, never collapsed behind a tool-call panel.

This applies to both the dashboard playground and the public-facing assistant.