Function measure_line_exempt 

pub fn measure_line_exempt(
    root: &Path,
    thresholds: Thresholds,
    omit: &[String],
    exempt_lines: &BTreeMap<String, BTreeSet<u32>>,
) -> Result<Outcome>

Diff-free Python coverage floor with line-scoped exemptions (#226): measure thresholds over every measured line except the exempt_lines. omit is the whole-file coverage exemptions, as in crate::coverage::measure. Requires coverage.py + pytest. The line-exempt path runs only when exempt_lines is non-empty; otherwise the caller takes the unchanged tool-total path.