Tool contract 6.19.1

Three small honesty fixes from the Gym's open questions and the usage audit.

• war_rivals rounds mean_fame and median_fame to whole fame and never said so, so recomputing them from the standings differed by half a point (0 and 4059 give 2030, not 2029.5). The note says it now.
• war_history.weeks[].finished_early is NULL on a week still in progress. It read false, which is the one wrong answer the flag exists to prevent: the week has not failed to reach the line, it has not had the chance, and a consumer filtering finished_early === false for weeks the clan did not close out was catching the live one.
• battles_query's limit description no longer implies 25 full battles is a safe page. A full row grew with tower hitpoints, elixir, the comparison block and a duel's rounds, and about ten can reach the result cap. The hard guard is unchanged on purpose - a page that fits should still be served, and the result_too_large refusal already prices the retry from the actual bytes.

Notes and descriptions, plus one null where a false was wrong.