The request ring only carried whole-request duration, so /v1/stats exposed no
first-token latency — the number that says how responsive a local model feels,
independent of decode speed. Streaming generations now stamp the first delta
they emit; non-streaming rows carry None and are skipped by the mean, so a
/health probe can never drag it toward zero.
Surfaced as requests.ttft_mean_ms in /v1/stats and in `ft ctl stats`.
jason-fxz
12ed695386