Discord report (corruption [BWC]): downloads coming through as the
instrumental cut when a vocal track was requested. The verification
step's `_normalize` function strips parentheticals and version-suffix
tags ("(Instrumental)", "- Live", etc) so legitimate name variations
don't false-fail the title-similarity check. That also means "In My
Feelings" and "In My Feelings (Instrumental)" both normalize to "in
my feelings", title similarity is 1.0, and the wrong cut passes
verification.
Detect the version label on each side BEFORE normalization runs. If
the expected and matched recordings disagree on version (one is
original, the other is instrumental / live / acoustic / remix /
etc), return FAIL — the fingerprint identified a real song, just
not the version the caller asked for.
Reuses `MusicMatchingEngine.detect_version_type` so the same regex
patterns the pre-download Soulseek matcher applies also drive
post-download verification. No duplicated tables.
Also gates the secondary fallback scan, so a wrong-version variant
sitting in the same fingerprint cluster can't win the loop after
the best match has already been version-rejected.
6 tests pin the behavior:
- instrumental returned for vocal request → FAIL
- vocal returned for instrumental request → FAIL
- live vs acoustic → FAIL
- matching versions on both sides → PASS
- original-to-original happy path → PASS (regression guard)
- secondary scan skips wrong-version recordings → not PASS
2194/2194 full suite green (was 2188 + 6 new).