Function build_report_data 

pub fn build_report_data(
    scan_result: &ScanResult,
    files: &[ProjectFile],
    conventions: Vec<AggregatedConvention>,
    db_path: &Path,
    elapsed: Duration,
    submodules_excluded_by_flag: bool,
) -> ReportData

Build ReportData from scan results and parsed files.

This is the single point of data collection for the report. It computes language breakdown from the in-memory file list, and dependency counts from manifest analysis results — no database queries needed.