The account-rotation while-loop entered with a signal.aborted /
stopAfterActive check (line 681) but then awaited _sleep(800) on
line 690 (waiting for main.js to resolve the next fallback) without
re-checking on the way out. If the user cancelled during that 800 ms
window the loop kept going — resolved the override, set up new
credentials, fired retrying-event, started a fresh attempt loop —
before _executeUpload's own signal handling finally noticed the
abort. Cancellation latency could therefore stretch by an extra
attempt's worth of work per still-spinning hoster.
One-line fix: add the same `if (signal.aborted || this.stopAfterActive)
break` after the await. Found by deep-audit MED-5.
126/126 tests still green; the fix is a guard on an already-tested
flow, no test infrastructure exists for cancel-during-rotation
specifically (would need fake-timer + mocked override-resolution).