Function is_unpinned_range 

pub fn is_unpinned_range(range: &str) -> bool

v0.17 [DECISION L] stub: a version range is unpinned — and rejected — when it is empty, */x/latest, or otherwise carries no concrete version number. A pinned range names at least one digit (^5, ~1.2, 1.2.3, >=1.0 <2). No allow-list or registry check yet.