pub fn parse_release_group(title: &str) -> Option<String>Expand description
Extract the release group from a release title.
This is a standalone post-cascade function — it operates on the ORIGINAL
un-preprocessed title, not the simple_title from the regex cascade.
Returns None when no release group is found, the group is purely numeric,
or the group matches the invalid-group pattern (e.g. S01, hex hashes).