Function safety_comments 

fn safety_comments(source: &str) -> Vec<String>

Collects contiguous // SAFETY: comment blocks in source order.

Comments are not part of Syn’s AST, so they are paired with AST operations by the visitor’s source order. This deliberately stores the rationale text, rather than a line number: moving or rewrapping a reviewed operation does not change its identity, while removing or silently replacing its proof does.