MaxRatio fails scene releases whose Subs archive contains a nested RAR (whole extraction fails, movie not imported) #796

Summary

Since the zip-bomb limits (#655, xtractr #176/#182/#185), a common scene layout fails every time with
extracted size exceeds maximum compression ratio: a Subs/*.subs.rar that contains a VobSub .idx
plus a nested .rar with the .sub. The real ratio of every archive involved is below 5, but the
shared extras budget pushes it over. Because the error fails the whole item, the main feature (which
extracted fine) is not imported either.

Versions

• unpackerr 0.16.1 (golift/unpackerr:latest, revision 1128), golift.io/xtractr v0.6.0
• Radarr item, torrent protocol, default settings (Starr MaxRatio = defaultMaxRatio 5.0)

Release layout

Autumn.Sonata.1978.REMASTERED.1080p.BluRay.x264-DEPTH (standard scene release):

Autumn...DEPTH/
  autumn...-depth.rar + .r00 … .r92      (100 MB volumes) -> Autumn...DEPTH.mkv  9,384,500,973 B
  Subs/autumn...-depth.subs.rar           1,891,221 B
        ├─ Autumn...DEPTH.idx                45,617 B
        └─ Autumn...DEPTH.rar             1,845,399 B   <- nested archive
              └─ Autumn...DEPTH.sub       8,957,952 B

Log

Extraction Queued: /data/downloads/_torrent/Autumn...DEPTH, retries: 0, 2 archives in 2 folders, delete orig: false
Extraction Started: Autumn...DEPTH
Extraction Failed: Autumn...DEPTH: extraction failed: extracted size exceeds maximum compression ratio
  (file: /data/downloads/_torrent/Autumn...DEPTH_unpackerred/Autumn...DEPTH.rar)
Status: Autumn...DEPTH (Extraction Failed, elapsed: 53m0s) on archive: 2/2 @ 0BB/8.5MB (0%)

The failing file is the nested …DEPTH.rar inside the _unpackerred output of subs.rar.

Why it trips

Per queue.go / progress.go, extras share the parent's tracker: Compressed stays the parent's size
("child sizes are not added") while Wrote keeps growing and includes the intermediate nested archive:

Actual ratios: subs.rar → 1.0×, nested .rar → .sub 4.85×, .idx+.sub vs subs.rar 4.76×.
The overshoot comes only from counting the nested archive's bytes as output while not counting them as
input.

Impact

• The whole item fails, so Radarr never imports the 9.4 GB .mkv although its extraction is fine
  (queue stays at "Found archive file, might need to be extracted"). Unpackerr retries and fails again.
• VobSub Subs/*.subs.rar with a nested .rar is the normal layout for many scene BluRay groups, so this
  affects a lot of older x264 releases.
• There is no knob for Starr items: max_ratio exists only for [[folder]]; Starr uses the constant
  defaultMaxRatio = 5.0.

Possible fixes (your call)

1. When an extra (nested archive) starts, add its own compressed size to the shared Compressed
   (or subtract it from Wrote, since it is intermediate data, not final output). Either keeps the cap
   meaningful for real bombs while a 1.9 MB → 9 MB subtitle pack passes.
2. Make the Starr MaxRatio configurable (like max_bytes / folder max_ratio), so users can raise it.
3. Optionally, a ratio failure in one archive of a multi-archive item could fail only that archive and
   still let the item import (the feature and the subtitles are independent archives in different folders).

Happy to test a build or provide the archives' headers if useful.