Function paceAfterTerminalRateLimit

Records the rate-limit reset deadline from a terminal 429, one that exhausted its retry budget, ran with retries disabled, or surfaced for any other reason without another attempt scheduled, so the next request to the same host waits for the window it already proved exhausted instead of dispatching immediately, eating another 429, and repeating until the window resets on its own.

The 429's rateLimit.reset metadata is already on the normalized error (parsed from the x-ratelimit-* headers of both HTTP-level and GraphQL-envelope 429s), so this is the failure-path counterpart of paceAfterSuccess: the same MAX_PACE_WAIT_MS clamp, the same recordPaceDeadline recorder. A 429 without rate-limit metadata records nothing; there is no reset deadline to wait for.