feat: Ability to configure a maximum number of queued/downloading torrents

[snow-away]

Problem statement

For users with a large amount of movies/shows under Wanted > Missing or Wanted > Cutoff Unmet implementing SearchMissing = true or QualityUnmetSearch = true for the first time can lead to many torrents being added and downloading at once. This can be a bit overwhelming for users, and can result in the torrents downloading slowly as they must share available download bandwidth.

Proposed solution

Adding a configuration option similar to the Pause When Queued setting in the Tubifarry Lidarr plugin's Search Sniper feature. This option would set a maximum number of items the *arr could have downloading at once. When the maximum is reached, new torrents aren't searched for until one/some of the currently downloading torrents are finished.

This could be implemented in the per-arr EntrySearch settings, perhaps:

[Sonarr-TV.EntrySearch]
MaxConcurrentDownloads = <integer>

Alternatives considered

I looked at SearchLimit but as far as I can tell that's only concerned with searches for torrents and not ongoing downloads.

Additional context

No response

Checklist

• I searched existing issues and discussions to avoid duplicates.
• I am willing to help validate or contribute to this feature.

[Feramance]

Is there a reason you wouldn't configure this within qbittorrent itself instead?

[snow-away]

By setting Maximum active downloads in qbittorrent? I'm embarrassed to say it hadn't occured to me 😅, that's a good idea. I suppose the proposed approach would allow more granular control per *arr. Say if I'm always adding a bunch of shows to Sonarr for friends, but want to fast-track a movie for myself, or if qBitrr is working through my Cutoff Unmet backlog I could manually trigger a search for something else I want now.

[Feramance]

It'll be tricky but I could look into it