The active probe recorded a network-layer failure as `false`, so a single
thrown fetch on the runner froze the production monitor at `auth.health=0`
while the service answered 200 throughout. It also required `/ready` on the
auth endpoint, which serves no such path, forcing every auth sample onto the
11s retry.
A thrown fetch now means "no reading" and is re-asked once after 1s; only a
second throw, or a non-ok response, yields false. `requiresReady` is threaded
per endpoint (director and cells true, auth false). Latency now measures the
answering round trip rather than probe wall time, so retry delays are not
reported as serving latency.