pub fn build_long_file_report(
root: &Path,
threshold: usize,
files: Option<&[PathBuf]>,
walk_config: &WalkConfig,
allow: &[String],
) -> DiagnosticsReportExpand description
Build a DiagnosticsReport for the long-file rule.
Walks all source files under root, counts lines, and emits an issue for
each file exceeding the threshold. Lock files and allow-listed paths are
skipped. allow should come from [rules.rule."long-file"] allow in config.