Multi-topic account discovery: given up to 25 topic_ids in one call,
return the companies showing intent across them. The fan-out runs in
parallel server-side, so a 25-topic request is about as fast as a single
topic.

group_by selects the response shape:

• entity (default): one row per company, annotated with which of the
  requested topics it shows intent on (topics), how many it matched
  (topic_count), and aggregate signals. Set min_topics to require a
  company match at least N of the topics (N = number of topics =
  intersection; default 1 = union). This view is cursor-paginated.
• topic: the raw per-topic ranked lists (the same fan-out, not
  merged), one bucket per requested topic.

min_score and min_people_count filter each topic's results.
per_topic_limit (default 1000, max 5000) caps how deep each topic is
scanned. min_topics, page_size, and cursor apply only to
group_by=entity.