qBittorrent's add call answers `Ok.` and nothing else — no hash, no name,
no duplicate signal — so arr derives the v1 infohash from the magnet or the
`.torrent` bytes before the call and looks the torrent up by it. That also
drops Transmission's numeric torrent id: the hash is the only identity now.
The reaper needs "stopped because a share limit was reached", and
qBittorrent's state field cannot tell that apart from a hand-paused torrent.
So the ratio and idle counters are checked against the limits arr set, and a
torrent stopped by a global limit reads as still seeding rather than being
deleted.
The WebUI needs a login, so `ARR_QBITTORRENT_USERNAME` and
`ARR_QBITTORRENT_PASSWORD` join the env-only secrets; leaving both unset is
valid for an instance that whitelists arr's subnet.
Verified against qBittorrent 5 (WebAPI 2.15.1) in a container: it rejects
`setShareLimits` without `shareLimitAction`, which 4.x ignores, so it is
always sent.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>