Function managed_skill_file_paths 

pub fn managed_skill_file_paths<'a>(
    filenames: impl Iterator<Item = &'a str>,
) -> BTreeSet<String>

Compute the subset of filenames that are skill-derived managed paths (the ones tracked in MANAGED_SKILL_FILES_MANIFEST) — everything else (CLAUDE.md, .mcp.json, .claude/settings.json, …) is always fully regenerated at a fixed path every launch, so it has no staleness problem to track.