Function parse_benchmark_dir 

pub fn parse_benchmark_dir(
    results_dir: &Path,
) -> Result<BTreeMap<String, BenchmarkMetric>, ParseBenchesError>

Scans the given directory for all *.txt files and parses their benchmark metrics.

Errors

Returns an error if:

• The directory does not exist (ParseBenchesError::DirectoryNotFound).
• No *.txt files are found (ParseBenchesError::NoTxtFiles).
• No metrics were parsed from any found files (ParseBenchesError::NoMetricsParsed).
• Duplicate benchmark metrics are detected across files.