Stored queue results never change, but terminal failures were saved as 502
and the page retried every 5xx, so users saw "reconnecting" indefinitely.
Pending and expired-link outcomes now answer 409, any other stored 5xx is
normalized to 422 (also for restored snapshots), lock failures are retried
by the worker, and the page reconnects only on network errors, 429, 502,
503 and 504.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>