Per-webhook retryMaxSecs is parsed, validated, stored, echoed back — and then ignored

The per-webhook retryMaxSecs config is fully round-tripped: parsed, validated, stored, and echoed back on read. But it has no effect. When the sender computes the give-up deadline, it always passes a hardcoded defaultRetryMaxSecs = 3 days, so whatever you configured is never consulted.

So if you set a short retry window expecting Talkyard to stop retrying a dead receiver sooner, it'll still retry for the default 3 days. Minor, but it's a config knob that silently does nothing — the same class of "parsed but ignored" issue that shows up in a few places in the API. It's marked [add_whk_conf] in the source.