PERF.69 Website: the developer API makes three writes per keyed call (last_used_at, throttle, request log), health polls included

DevKeys::inspect runs UPDATE a Discord member_api_keys SET last_used_at, Throttle::hit an INSERT and DevApi::log an INSERT on every call, 200s on /v1/health and 404s too; each autocommit is an fsync with innodb_flush_log_at_trx_commit 1. Load test: api host /v1/health 679 req/s, /v1/endpoints 763, /v1/status 364 at c=10, zero failures (the floors are fine: health 3.6 ms). At 1000x (an integrator polling once a second) the writes are the cost. Change: update last_used_at at most once a minute per key, skip the request log for health 200s, keep it for everything else; a Discord member_api_requests is pruned at 30 days already.