Get Requirement Summaries

Per requirement: how often it has been checked, how it came out, and what reviewers said.

One grouped query for a whole page of the library. The per-requirement route below answers the same question in full, with the collateral listed; this one is what a list can afford to ask.

Requirements with no checks are omitted rather than returned as zeros. A row shows this strip only when there is something to say, so a caller keying a map on the response gets undefined for exactly the rows that should render nothing.