Backup dialog interferring with add-on's QueryOp

> Hi. I’m writing an add-on that generates audio files and uses an external Python script. Since Anki creates a new backup every 5 minutes and opens a modal window (“Creating backup”), the add-on window completely loses focus, making it impossible to cancel the queue even if I want to. And the best part is that the backup window just stays there indefinitely.
> I’m curious if there’s a way to pause backups while the add-on is running.
> 2026-03-14_00-041920×1080 592 KB

Originally reported on https://forums.ankiweb.net/t/pause-disable-backups-during-background-tasks/69151

The backup task is also run in a QueryOp with collection_executor. The task doesn't start until all scheduled tasks are done (due to max_workers=1), but progress.start() is called immediately before the task is scheduled.

Start by tracing the backup task through QueryOp and collection_executor, paying attention to the timing of progress.start() and the single-worker scheduling described in the issue. Done should mean scheduled add-on work can remain usable while backups run, without the backup dialog indefinitely taking focus.

Written by the indexing model from the issue text.