[Bug] Fix remove_orphans deleting active downloads (#322)

[keez97]

Fixes #322.

get_queue_items("orphans") computed orphans as [fq for fq in full_queue if fq not in normal_queue], comparing whole records. The two fetches are separate requests after a RefreshMonitoredDownloads, so sizeleft / timeleft / estimatedCompletionTime of an actively downloading item differ between them. The record comparison then fails and the download is treated as an orphan and removed (without blocklist, since RemoveOrphans.blocklist = False). Paused and stalled items never change between the fetches, which is why only healthy downloads were hit.

Change: compare by queue item id instead of by record.

• src/utils/queue_manager.py: build a set of ids from the normal queue and keep full-queue items whose id is not in it
• tests/utils/test_queue_manager.py: regression test where the same item has a different sizeleft in the two fetches; fails on the old code, passes on the new

Full suite: 293 passed.

Verified on my Radarr/Sonarr + qBittorrent stack: the old image deleted three actively downloading remuxes over two days; the patched image ran three 5-minute cycles against a download progressing at ~3 MB/s with no removal.

[lolimmlost]

Reviewed and tested locally. LGTM.

The root cause matches the analysis in #322: the full and normal queue fetches are separate requests, so progress fields (sizeleft, timeleft, estimatedCompletionTime) on an active download differ between them and the whole-record not in check flags it as an orphan. Comparing by queue item id is the right fix, since the *arr queue id is derived from the download and the media item and is stable across back-to-back fetches.

Verified:

• Full test suite passes (293 passed).
• The new regression test fails against current dev (1 failed) and passes with the fix, so it actually covers the bug.
• This was the only place in src/ doing a whole-record queue comparison, so there are no other instances of the same pattern.
• If an item were ever missing id, None matches None and it is not treated as an orphan, which fails safe (no deletion).

Nit (non-blocking): there are 3 blank lines before the new test in tests/utils/test_queue_manager.py; PEP 8 / ruff E303 wants 2.

[ManiMatter]

@lolimmlost feel free to directly merge any PRs you approve. Full trust :)