handleProgress on a 'done' event with removeFromQueueOnDone=true was
calling queueJobs.filter() once per event. With 500 parallel jobs all
finishing at roughly the same time, that's 500 × O(N) = O(N²) work
synchronously on the IPC handler thread — visible as a brief UI freeze
when a big batch completes.
Coalesce into one microtask: removeJobFromIndex + selection cleanup
stay synchronous (so subsequent lookups see the right state), but the
array rewrite is deferred to a single filter against a Set of all
ids that came in this tick. JS microtask runs after the sync IPC
batch, so within one batch-of-events we get one filter pass instead
of N.
beforeunload drains the pending set synchronously before persisting
so removeFromQueueOnDone=true users don't see jobs reappear after
restart that they expected to be gone.
38ecc6a4cb