Read one result found via search as plain text with its public page URL, for quoting or citing it in an answer; this is the fetch half of the search/fetch pair. Pass the result's id exactly as search returned it (e.g. "course:..."). Returns {id, title, text, url, metadata}. A course's text is its public catalog summary (name, description, level, duration in hours, price, subjects, topics), not its lessons. A missing document, another site's content, and a type this connection cannot read all return the same not-found error; an id without a type prefix is rejected as invalid. To work with a course rather than quote it, use course_get for its settings record (ids, flags, dates, enrollment count) and course_content_get for its lessons as EditorJS blocks.
