e621 intermittently answers 429 to the IQDB endpoint; browsers hide that
status behind CORS ('Access-Control-Allow-Origin missing'), so the SPA
cannot read it. Treat every network-level failure as a possible rate limit
and pause all e621 traffic for a minute. The cooldown is shared through
localStorage so extra tabs respect it, requests are spaced 1.5s apart
instead of 1s, user-cancelled requests do not trigger a cooldown, and the
upload queue waits the cooldown out with a countdown instead of looking
stuck.
Server side: the per-process e621 gap goes from 0.5s to 1s so two gunicorn
workers cannot together exceed e621's 2/s hard limit.
JakeBreath
9641862515